Node.js v24.0.0 文档

严格断言模式#

在严格断言模式下，非严格方法的行为类似于它们对应的严格方法。 例如，assert.deepEqual() 的行为类似于 assert.deepStrictEqual()。

在严格断言模式下，对象的错误消息会显示差异。 在旧式断言模式下，对象的错误消息会显示对象，通常会被截断。

使用严格断言模式

import { strict as assert } from 'node:assert';const assert = require('node:assert').strict;copy

import assert from 'node:assert/strict';const assert = require('node:assert/strict');copy

错误差异示例

import { strict as assert } from 'node:assert';

assert.deepEqual([[[1, 2, 3]], 4, 5], [[[1, 2, '3']], 4, 5]);
// AssertionError: Expected inputs to be strictly deep-equal:
// + actual - expected ... Lines skipped
//
//   [
//     [
// ...
//       2,
// +     3
// -     '3'
//     ],
// ...
//     5
//   ]const assert = require('node:assert/strict');

assert.deepEqual([[[1, 2, 3]], 4, 5], [[[1, 2, '3']], 4, 5]);
// AssertionError: Expected inputs to be strictly deep-equal:
// + actual - expected ... Lines skipped
//
//   [
//     [
// ...
//       2,
// +     3
// -     '3'
//     ],
// ...
//     5
//   ]copy

要停用颜色，请使用 NO_COLOR 或 NODE_DISABLE_COLORS 环境变量。 这也会停用 REPL 中的颜色。 有关终端环境中颜色支持的更多信息，请阅读 tty getColorDepth() 文档。

旧式断言模式#

旧式断言模式使用 == 运算符 在

• assert.deepEqual()
• assert.equal()
• assert.notDeepEqual()
• assert.notEqual()

使用旧式断言模式

import assert from 'node:assert';const assert = require('node:assert');copy

旧式断言模式可能会产生令人惊讶的结果，尤其是在使用 assert.deepEqual() 时

// WARNING: This does not throw an AssertionError in legacy assertion mode!
assert.deepEqual(/a/gi, new Date()); copy

类：assert.AssertionError[src]#

• 继承自：<errors.Error>

表示断言失败。 由 node:assert 模块抛出的所有错误都将是 AssertionError 类的实例。

import assert from 'node:assert';

// Generate an AssertionError to compare the error message later:
const { message } = new assert.AssertionError({
  actual: 1,
  expected: 2,
  operator: 'strictEqual',
});

// Verify error output:
try {
  assert.strictEqual(1, 2);
} catch (err) {
  assert(err instanceof assert.AssertionError);
  assert.strictEqual(err.message, message);
  assert.strictEqual(err.name, 'AssertionError');
  assert.strictEqual(err.actual, 1);
  assert.strictEqual(err.expected, 2);
  assert.strictEqual(err.code, 'ERR_ASSERTION');
  assert.strictEqual(err.operator, 'strictEqual');
  assert.strictEqual(err.generatedMessage, true);
}const assert = require('node:assert');

// Generate an AssertionError to compare the error message later:
const { message } = new assert.AssertionError({
  actual: 1,
  expected: 2,
  operator: 'strictEqual',
});

// Verify error output:
try {
  assert.strictEqual(1, 2);
} catch (err) {
  assert(err instanceof assert.AssertionError);
  assert.strictEqual(err.message, message);
  assert.strictEqual(err.name, 'AssertionError');
  assert.strictEqual(err.actual, 1);
  assert.strictEqual(err.expected, 2);
  assert.strictEqual(err.code, 'ERR_ASSERTION');
  assert.strictEqual(err.operator, 'strictEqual');
  assert.strictEqual(err.generatedMessage, true);
}copy

类：assert.CallTracker#

此功能已弃用，将在未来的版本中删除。 请考虑使用诸如 mock 辅助函数之类的替代方案。

import assert from 'node:assert';
import process from 'node:process';

const tracker = new assert.CallTracker();

function func() {}

// callsfunc() must be called exactly 1 time before tracker.verify().
const callsfunc = tracker.calls(func, 1);

callsfunc();

// Calls tracker.verify() and verifies if all tracker.calls() functions have
// been called exact times.
process.on('exit', () => {
  tracker.verify();
});const assert = require('node:assert');
const process = require('node:process');

const tracker = new assert.CallTracker();

function func() {}

// callsfunc() must be called exactly 1 time before tracker.verify().
const callsfunc = tracker.calls(func, 1);

callsfunc();

// Calls tracker.verify() and verifies if all tracker.calls() functions have
// been called exact times.
process.on('exit', () => {
  tracker.verify();
});copy

import assert from 'node:assert';

// Creates call tracker.
const tracker = new assert.CallTracker();

function func() {}

// Returns a function that wraps func() that must be called exact times
// before tracker.verify().
const callsfunc = tracker.calls(func);const assert = require('node:assert');

// Creates call tracker.
const tracker = new assert.CallTracker();

function func() {}

// Returns a function that wraps func() that must be called exact times
// before tracker.verify().
const callsfunc = tracker.calls(func);copy

import assert from 'node:assert';

const tracker = new assert.CallTracker();

function func() {}
const callsfunc = tracker.calls(func);
callsfunc(1, 2, 3);

assert.deepStrictEqual(tracker.getCalls(callsfunc),
                       [{ thisArg: undefined, arguments: [1, 2, 3] }]);const assert = require('node:assert');

// Creates call tracker.
const tracker = new assert.CallTracker();

function func() {}
const callsfunc = tracker.calls(func);
callsfunc(1, 2, 3);

assert.deepStrictEqual(tracker.getCalls(callsfunc),
                       [{ thisArg: undefined, arguments: [1, 2, 3] }]);copy

import assert from 'node:assert';

// Creates call tracker.
const tracker = new assert.CallTracker();

function func() {}

// Returns a function that wraps func() that must be called exact times
// before tracker.verify().
const callsfunc = tracker.calls(func, 2);

// Returns an array containing information on callsfunc()
console.log(tracker.report());
// [
//  {
//    message: 'Expected the func function to be executed 2 time(s) but was
//    executed 0 time(s).',
//    actual: 0,
//    expected: 2,
//    operator: 'func',
//    stack: stack trace
//  }
// ]const assert = require('node:assert');

// Creates call tracker.
const tracker = new assert.CallTracker();

function func() {}

// Returns a function that wraps func() that must be called exact times
// before tracker.verify().
const callsfunc = tracker.calls(func, 2);

// Returns an array containing information on callsfunc()
console.log(tracker.report());
// [
//  {
//    message: 'Expected the func function to be executed 2 time(s) but was
//    executed 0 time(s).',
//    actual: 0,
//    expected: 2,
//    operator: 'func',
//    stack: stack trace
//  }
// ]copy

import assert from 'node:assert';

const tracker = new assert.CallTracker();

function func() {}
const callsfunc = tracker.calls(func);

callsfunc();
// Tracker was called once
assert.strictEqual(tracker.getCalls(callsfunc).length, 1);

tracker.reset(callsfunc);
assert.strictEqual(tracker.getCalls(callsfunc).length, 0);const assert = require('node:assert');

const tracker = new assert.CallTracker();

function func() {}
const callsfunc = tracker.calls(func);

callsfunc();
// Tracker was called once
assert.strictEqual(tracker.getCalls(callsfunc).length, 1);

tracker.reset(callsfunc);
assert.strictEqual(tracker.getCalls(callsfunc).length, 0);copy

import assert from 'node:assert';

// Creates call tracker.
const tracker = new assert.CallTracker();

function func() {}

// Returns a function that wraps func() that must be called exact times
// before tracker.verify().
const callsfunc = tracker.calls(func, 2);

callsfunc();

// Will throw an error since callsfunc() was only called once.
tracker.verify();const assert = require('node:assert');

// Creates call tracker.
const tracker = new assert.CallTracker();

function func() {}

// Returns a function that wraps func() that must be called exact times
// before tracker.verify().
const callsfunc = tracker.calls(func, 2);

callsfunc();

// Will throw an error since callsfunc() was only called once.
tracker.verify();copy

assert(value[, message])#

• value <any> 检查是否为真值的输入。
• message <string> | <Error>

是 assert.ok() 的别名。

assert.deepEqual(actual, expected[, message])#

• actual <any>
• expected <any>
• message <string> | <Error>

严格断言模式

是 assert.deepStrictEqual() 的别名。

旧式断言模式

测试 actual 和 expected 参数之间的深度相等性。 考虑改用 assert.deepStrictEqual()。 assert.deepEqual() 可能会产生令人惊讶的结果。

深度相等是指子对象的可枚举的“自有”属性也通过以下规则进行递归评估。

import assert from 'node:assert';
// WARNING: This does not throw an AssertionError!

assert.deepEqual('+00000000', false);const assert = require('node:assert');
// WARNING: This does not throw an AssertionError!

assert.deepEqual('+00000000', false);copy

import assert from 'node:assert';

const obj1 = {
  a: {
    b: 1,
  },
};
const obj2 = {
  a: {
    b: 2,
  },
};
const obj3 = {
  a: {
    b: 1,
  },
};
const obj4 = { __proto__: obj1 };

assert.deepEqual(obj1, obj1);
// OK

// Values of b are different:
assert.deepEqual(obj1, obj2);
// AssertionError: { a: { b: 1 } } deepEqual { a: { b: 2 } }

assert.deepEqual(obj1, obj3);
// OK

// Prototypes are ignored:
assert.deepEqual(obj1, obj4);
// AssertionError: { a: { b: 1 } } deepEqual {}const assert = require('node:assert');

const obj1 = {
  a: {
    b: 1,
  },
};
const obj2 = {
  a: {
    b: 2,
  },
};
const obj3 = {
  a: {
    b: 1,
  },
};
const obj4 = { __proto__: obj1 };

assert.deepEqual(obj1, obj1);
// OK

// Values of b are different:
assert.deepEqual(obj1, obj2);
// AssertionError: { a: { b: 1 } } deepEqual { a: { b: 2 } }

assert.deepEqual(obj1, obj3);
// OK

// Prototypes are ignored:
assert.deepEqual(obj1, obj4);
// AssertionError: { a: { b: 1 } } deepEqual {}copy

assert.deepStrictEqual(actual, expected[, message])#

• actual <any>
• expected <any>
• message <string> | <Error>

测试 actual 和 expected 参数之间的深度相等性。“深度”相等意味着子对象的可枚举的“自有”属性也通过以下规则进行递归评估。

import assert from 'node:assert/strict';

// This fails because 1 !== '1'.
assert.deepStrictEqual({ a: 1 }, { a: '1' });
// AssertionError: Expected inputs to be strictly deep-equal:
// + actual - expected
//
//   {
// +   a: 1
// -   a: '1'
//   }

// The following objects don't have own properties
const date = new Date();
const object = {};
const fakeDate = {};
Object.setPrototypeOf(fakeDate, Date.prototype);

// Different [[Prototype]]:
assert.deepStrictEqual(object, fakeDate);
// AssertionError: Expected inputs to be strictly deep-equal:
// + actual - expected
//
// + {}
// - Date {}

// Different type tags:
assert.deepStrictEqual(date, fakeDate);
// AssertionError: Expected inputs to be strictly deep-equal:
// + actual - expected
//
// + 2018-04-26T00:49:08.604Z
// - Date {}

assert.deepStrictEqual(NaN, NaN);
// OK because Object.is(NaN, NaN) is true.

// Different unwrapped numbers:
assert.deepStrictEqual(new Number(1), new Number(2));
// AssertionError: Expected inputs to be strictly deep-equal:
// + actual - expected
//
// + [Number: 1]
// - [Number: 2]

assert.deepStrictEqual(new String('foo'), Object('foo'));
// OK because the object and the string are identical when unwrapped.

assert.deepStrictEqual(-0, -0);
// OK

// Different zeros:
assert.deepStrictEqual(0, -0);
// AssertionError: Expected inputs to be strictly deep-equal:
// + actual - expected
//
// + 0
// - -0

const symbol1 = Symbol();
const symbol2 = Symbol();
assert.deepStrictEqual({ [symbol1]: 1 }, { [symbol1]: 1 });
// OK, because it is the same symbol on both objects.

assert.deepStrictEqual({ [symbol1]: 1 }, { [symbol2]: 1 });
// AssertionError [ERR_ASSERTION]: Inputs identical but not reference equal:
//
// {
//   Symbol(): 1
// }

const weakMap1 = new WeakMap();
const weakMap2 = new WeakMap();
const obj = {};

weakMap1.set(obj, 'value');
weakMap2.set(obj, 'value');

// Comparing different instances fails, even with same contents
assert.deepStrictEqual(weakMap1, weakMap2);
// AssertionError: Values have same structure but are not reference-equal:
//
// WeakMap {
//   <items unknown>
// }

// Comparing the same instance to itself succeeds
assert.deepStrictEqual(weakMap1, weakMap1);
// OK

const weakSet1 = new WeakSet();
const weakSet2 = new WeakSet();
weakSet1.add(obj);
weakSet2.add(obj);

// Comparing different instances fails, even with same contents
assert.deepStrictEqual(weakSet1, weakSet2);
// AssertionError: Values have same structure but are not reference-equal:
// + actual - expected
//
// WeakSet {
//   <items unknown>
// }

// Comparing the same instance to itself succeeds
assert.deepStrictEqual(weakSet1, weakSet1);
// OKconst assert = require('node:assert/strict');

// This fails because 1 !== '1'.
assert.deepStrictEqual({ a: 1 }, { a: '1' });
// AssertionError: Expected inputs to be strictly deep-equal:
// + actual - expected
//
//   {
// +   a: 1
// -   a: '1'
//   }

// The following objects don't have own properties
const date = new Date();
const object = {};
const fakeDate = {};
Object.setPrototypeOf(fakeDate, Date.prototype);

// Different [[Prototype]]:
assert.deepStrictEqual(object, fakeDate);
// AssertionError: Expected inputs to be strictly deep-equal:
// + actual - expected
//
// + {}
// - Date {}

// Different type tags:
assert.deepStrictEqual(date, fakeDate);
// AssertionError: Expected inputs to be strictly deep-equal:
// + actual - expected
//
// + 2018-04-26T00:49:08.604Z
// - Date {}

assert.deepStrictEqual(NaN, NaN);
// OK because Object.is(NaN, NaN) is true.

// Different unwrapped numbers:
assert.deepStrictEqual(new Number(1), new Number(2));
// AssertionError: Expected inputs to be strictly deep-equal:
// + actual - expected
//
// + [Number: 1]
// - [Number: 2]

assert.deepStrictEqual(new String('foo'), Object('foo'));
// OK because the object and the string are identical when unwrapped.

assert.deepStrictEqual(-0, -0);
// OK

// Different zeros:
assert.deepStrictEqual(0, -0);
// AssertionError: Expected inputs to be strictly deep-equal:
// + actual - expected
//
// + 0
// - -0

const symbol1 = Symbol();
const symbol2 = Symbol();
assert.deepStrictEqual({ [symbol1]: 1 }, { [symbol1]: 1 });
// OK, because it is the same symbol on both objects.

assert.deepStrictEqual({ [symbol1]: 1 }, { [symbol2]: 1 });
// AssertionError [ERR_ASSERTION]: Inputs identical but not reference equal:
//
// {
//   Symbol(): 1
// }

const weakMap1 = new WeakMap();
const weakMap2 = new WeakMap();
const obj = {};

weakMap1.set(obj, 'value');
weakMap2.set(obj, 'value');

// Comparing different instances fails, even with same contents
assert.deepStrictEqual(weakMap1, weakMap2);
// AssertionError: Values have same structure but are not reference-equal:
//
// WeakMap {
//   <items unknown>
// }

// Comparing the same instance to itself succeeds
assert.deepStrictEqual(weakMap1, weakMap1);
// OK

const weakSet1 = new WeakSet();
const weakSet2 = new WeakSet();
weakSet1.add(obj);
weakSet2.add(obj);

// Comparing different instances fails, even with same contents
assert.deepStrictEqual(weakSet1, weakSet2);
// AssertionError: Values have same structure but are not reference-equal:
// + actual - expected
//
// WeakSet {
//   <items unknown>
// }

// Comparing the same instance to itself succeeds
assert.deepStrictEqual(weakSet1, weakSet1);
// OKcopy

assert.doesNotMatch(string, regexp[, message])#

• string <string>
• regexp <RegExp>
• message <string> | <Error>

期望 string 输入与正则表达式不匹配。

import assert from 'node:assert/strict';

assert.doesNotMatch('I will fail', /fail/);
// AssertionError [ERR_ASSERTION]: The input was expected to not match the ...

assert.doesNotMatch(123, /pass/);
// AssertionError [ERR_ASSERTION]: The "string" argument must be of type string.

assert.doesNotMatch('I will pass', /different/);
// OKconst assert = require('node:assert/strict');

assert.doesNotMatch('I will fail', /fail/);
// AssertionError [ERR_ASSERTION]: The input was expected to not match the ...

assert.doesNotMatch(123, /pass/);
// AssertionError [ERR_ASSERTION]: The "string" argument must be of type string.

assert.doesNotMatch('I will pass', /different/);
// OKcopy

如果值匹配，或者 string 参数的类型不是 string，则会抛出一个 AssertionError，其 message 属性设置为 message 参数的值。如果 message 参数未定义，则会分配一个默认错误消息。如果 message 参数是 <Error> 的实例，则会抛出它，而不是 AssertionError。

assert.doesNotReject(asyncFn[, error][, message])#

• asyncFn <Function> | <Promise>
• error <RegExp> | <Function>
• message <string>
• 返回: <Promise>

等待 asyncFn Promise，或者，如果 asyncFn 是一个函数，则立即调用该函数并等待返回的 Promise 完成。然后它会检查 Promise 是否未被拒绝。

如果 asyncFn 是一个函数并且它同步抛出一个错误，则 assert.doesNotReject() 将返回一个被拒绝的 Promise，其中包含该错误。 如果函数没有返回 Promise，则 assert.doesNotReject() 将返回一个被拒绝的 Promise，其中包含 ERR_INVALID_RETURN_VALUE 错误。 在这两种情况下，错误处理程序都会被跳过。

使用 assert.doesNotReject() 实际上没有用处，因为捕获拒绝然后再次拒绝它的好处很小。 而是考虑在不应拒绝的特定代码路径旁边添加注释，并使错误消息尽可能具有表现力。

如果指定了 error，则 error 可以是 Class、<RegExp> 或验证函数。 有关更多详细信息，请参见 assert.throws()。

除了等待完成的异步特性外，其行为与 assert.doesNotThrow() 相同。

import assert from 'node:assert/strict';

await assert.doesNotReject(
  async () => {
    throw new TypeError('Wrong value');
  },
  SyntaxError,
);const assert = require('node:assert/strict');

(async () => {
  await assert.doesNotReject(
    async () => {
      throw new TypeError('Wrong value');
    },
    SyntaxError,
  );
})();copy

import assert from 'node:assert/strict';

assert.doesNotReject(Promise.reject(new TypeError('Wrong value')))
  .then(() => {
    // ...
  });const assert = require('node:assert/strict');

assert.doesNotReject(Promise.reject(new TypeError('Wrong value')))
  .then(() => {
    // ...
  });copy

assert.doesNotThrow(fn[, error][, message])#

• fn <Function>
• error <RegExp> | <Function>
• message <string>

断言函数 fn 没有抛出错误。

使用 assert.doesNotThrow() 实际上没有用处，因为捕获错误然后重新抛出它没有任何好处。 而是考虑在不应抛出的特定代码路径旁边添加注释，并使错误消息尽可能具有表现力。

当调用 assert.doesNotThrow() 时，它将立即调用 fn 函数。

如果抛出了一个错误，并且该错误与 error 参数指定的类型相同，则会抛出一个 AssertionError。 如果该错误是另一种类型，或者如果 error 参数未定义，则该错误会传播回调用方。

如果指定了 error，则 error 可以是 Class、<RegExp> 或验证函数。 有关更多详细信息，请参见 assert.throws()。

例如，以下内容将抛出 <TypeError>，因为断言中没有匹配的错误类型

import assert from 'node:assert/strict';

assert.doesNotThrow(
  () => {
    throw new TypeError('Wrong value');
  },
  SyntaxError,
);const assert = require('node:assert/strict');

assert.doesNotThrow(
  () => {
    throw new TypeError('Wrong value');
  },
  SyntaxError,
);copy

但是，以下代码将导致一个 AssertionError，其中包含消息“Got unwanted exception...”

import assert from 'node:assert/strict';

assert.doesNotThrow(
  () => {
    throw new TypeError('Wrong value');
  },
  TypeError,
);const assert = require('node:assert/strict');

assert.doesNotThrow(
  () => {
    throw new TypeError('Wrong value');
  },
  TypeError,
);copy

如果抛出了一个 AssertionError，并且为 message 参数提供了一个值，则 message 的值将附加到 AssertionError 消息

import assert from 'node:assert/strict';

assert.doesNotThrow(
  () => {
    throw new TypeError('Wrong value');
  },
  /Wrong value/,
  'Whoops',
);
// Throws: AssertionError: Got unwanted exception: Whoopsconst assert = require('node:assert/strict');

assert.doesNotThrow(
  () => {
    throw new TypeError('Wrong value');
  },
  /Wrong value/,
  'Whoops',
);
// Throws: AssertionError: Got unwanted exception: Whoopscopy

assert.equal(actual, expected[, message])#

• actual <any>
• expected <any>
• message <string> | <Error>

严格断言模式

是 assert.strictEqual() 的别名。

旧式断言模式

使用 == 运算符测试 actual 和 expected 参数之间的浅层、强制相等。 NaN 经过特殊处理，如果两边都是 NaN，则将其视为相同。

import assert from 'node:assert';

assert.equal(1, 1);
// OK, 1 == 1
assert.equal(1, '1');
// OK, 1 == '1'
assert.equal(NaN, NaN);
// OK

assert.equal(1, 2);
// AssertionError: 1 == 2
assert.equal({ a: { b: 1 } }, { a: { b: 1 } });
// AssertionError: { a: { b: 1 } } == { a: { b: 1 } }const assert = require('node:assert');

assert.equal(1, 1);
// OK, 1 == 1
assert.equal(1, '1');
// OK, 1 == '1'
assert.equal(NaN, NaN);
// OK

assert.equal(1, 2);
// AssertionError: 1 == 2
assert.equal({ a: { b: 1 } }, { a: { b: 1 } });
// AssertionError: { a: { b: 1 } } == { a: { b: 1 } }copy

如果值不相等，则会抛出一个 AssertionError，其中 message 属性设置为等于 message 参数的值。 如果 message 参数未定义，则会分配一个默认错误消息。 如果 message 参数是 <Error> 的实例，则会抛出该实例而不是 AssertionError。

assert.fail([message])#

• message <string> | <Error> 默认: 'Failed'

抛出一个 AssertionError，其中包含提供的错误消息或默认错误消息。 如果 message 参数是 <Error> 的实例，则会抛出它，而不是 AssertionError。

import assert from 'node:assert/strict';

assert.fail();
// AssertionError [ERR_ASSERTION]: Failed

assert.fail('boom');
// AssertionError [ERR_ASSERTION]: boom

assert.fail(new TypeError('need array'));
// TypeError: need arrayconst assert = require('node:assert/strict');

assert.fail();
// AssertionError [ERR_ASSERTION]: Failed

assert.fail('boom');
// AssertionError [ERR_ASSERTION]: boom

assert.fail(new TypeError('need array'));
// TypeError: need arraycopy

可以使用带有两个以上参数的 assert.fail()，但不建议这样做。 请参阅下文了解更多详细信息。

assert.fail(actual, expected[, message[, operator[, stackStartFn]]])#

• actual <any>
• expected <any>
• message <string> | <Error>
• operator <string> 默认: '!='
• stackStartFn <Function> 默认: assert.fail

如果 message 是假值，则错误消息设置为由提供的 operator 分隔的 actual 和 expected 的值。 如果仅提供了两个 actual 和 expected 参数，则 operator 将默认为 '!='。 如果 message 作为第三个参数提供，它将被用作错误消息，并且其他参数将作为属性存储在抛出的对象上。 如果提供了 stackStartFn，则该函数之上的所有堆栈帧都将从堆栈跟踪中删除（请参见 Error.captureStackTrace）。 如果未提供任何参数，则将使用默认消息 Failed。

import assert from 'node:assert/strict';

assert.fail('a', 'b');
// AssertionError [ERR_ASSERTION]: 'a' != 'b'

assert.fail(1, 2, undefined, '>');
// AssertionError [ERR_ASSERTION]: 1 > 2

assert.fail(1, 2, 'fail');
// AssertionError [ERR_ASSERTION]: fail

assert.fail(1, 2, 'whoops', '>');
// AssertionError [ERR_ASSERTION]: whoops

assert.fail(1, 2, new TypeError('need array'));
// TypeError: need arrayconst assert = require('node:assert/strict');

assert.fail('a', 'b');
// AssertionError [ERR_ASSERTION]: 'a' != 'b'

assert.fail(1, 2, undefined, '>');
// AssertionError [ERR_ASSERTION]: 1 > 2

assert.fail(1, 2, 'fail');
// AssertionError [ERR_ASSERTION]: fail

assert.fail(1, 2, 'whoops', '>');
// AssertionError [ERR_ASSERTION]: whoops

assert.fail(1, 2, new TypeError('need array'));
// TypeError: need arraycopy

在最后三种情况下，actual、expected 和 operator 对错误消息没有影响。

使用 stackStartFn 截断异常堆栈跟踪的示例

import assert from 'node:assert/strict';

function suppressFrame() {
  assert.fail('a', 'b', undefined, '!==', suppressFrame);
}
suppressFrame();
// AssertionError [ERR_ASSERTION]: 'a' !== 'b'
//     at repl:1:1
//     at ContextifyScript.Script.runInThisContext (vm.js:44:33)
//     ...const assert = require('node:assert/strict');

function suppressFrame() {
  assert.fail('a', 'b', undefined, '!==', suppressFrame);
}
suppressFrame();
// AssertionError [ERR_ASSERTION]: 'a' !== 'b'
//     at repl:1:1
//     at ContextifyScript.Script.runInThisContext (vm.js:44:33)
//     ...copy

assert.ifError(value)#

• value <any>

如果 value 不是 undefined 或 null，则抛出 value。 这在测试回调中的 error 参数时很有用。 堆栈跟踪包含从传递给 ifError() 的错误中的所有帧，包括 ifError() 本身可能的新帧。

import assert from 'node:assert/strict';

assert.ifError(null);
// OK
assert.ifError(0);
// AssertionError [ERR_ASSERTION]: ifError got unwanted exception: 0
assert.ifError('error');
// AssertionError [ERR_ASSERTION]: ifError got unwanted exception: 'error'
assert.ifError(new Error());
// AssertionError [ERR_ASSERTION]: ifError got unwanted exception: Error

// Create some random error frames.
let err;
(function errorFrame() {
  err = new Error('test error');
})();

(function ifErrorFrame() {
  assert.ifError(err);
})();
// AssertionError [ERR_ASSERTION]: ifError got unwanted exception: test error
//     at ifErrorFrame
//     at errorFrameconst assert = require('node:assert/strict');

assert.ifError(null);
// OK
assert.ifError(0);
// AssertionError [ERR_ASSERTION]: ifError got unwanted exception: 0
assert.ifError('error');
// AssertionError [ERR_ASSERTION]: ifError got unwanted exception: 'error'
assert.ifError(new Error());
// AssertionError [ERR_ASSERTION]: ifError got unwanted exception: Error

// Create some random error frames.
let err;
(function errorFrame() {
  err = new Error('test error');
})();

(function ifErrorFrame() {
  assert.ifError(err);
})();
// AssertionError [ERR_ASSERTION]: ifError got unwanted exception: test error
//     at ifErrorFrame
//     at errorFramecopy

assert.match(string, regexp[, message])#

• string <string>
• regexp <RegExp>
• message <string> | <Error>

期望 string 输入与正则表达式匹配。

import assert from 'node:assert/strict';

assert.match('I will fail', /pass/);
// AssertionError [ERR_ASSERTION]: The input did not match the regular ...

assert.match(123, /pass/);
// AssertionError [ERR_ASSERTION]: The "string" argument must be of type string.

assert.match('I will pass', /pass/);
// OKconst assert = require('node:assert/strict');

assert.match('I will fail', /pass/);
// AssertionError [ERR_ASSERTION]: The input did not match the regular ...

assert.match(123, /pass/);
// AssertionError [ERR_ASSERTION]: The "string" argument must be of type string.

assert.match('I will pass', /pass/);
// OKcopy

如果值不匹配，或者 string 参数的类型不是 string，则会抛出一个 AssertionError，其 message 属性设置为 message 参数的值。如果 message 参数未定义，则会分配一个默认错误消息。如果 message 参数是 <Error> 的实例，则会抛出它，而不是 AssertionError。

assert.notDeepEqual(actual, expected[, message])#

• actual <any>
• expected <any>
• message <string> | <Error>

严格断言模式

是 assert.notDeepStrictEqual() 的别名。

旧式断言模式

测试任何深度不相等。 与 assert.deepEqual() 相反。

import assert from 'node:assert';

const obj1 = {
  a: {
    b: 1,
  },
};
const obj2 = {
  a: {
    b: 2,
  },
};
const obj3 = {
  a: {
    b: 1,
  },
};
const obj4 = { __proto__: obj1 };

assert.notDeepEqual(obj1, obj1);
// AssertionError: { a: { b: 1 } } notDeepEqual { a: { b: 1 } }

assert.notDeepEqual(obj1, obj2);
// OK

assert.notDeepEqual(obj1, obj3);
// AssertionError: { a: { b: 1 } } notDeepEqual { a: { b: 1 } }

assert.notDeepEqual(obj1, obj4);
// OKconst assert = require('node:assert');

const obj1 = {
  a: {
    b: 1,
  },
};
const obj2 = {
  a: {
    b: 2,
  },
};
const obj3 = {
  a: {
    b: 1,
  },
};
const obj4 = { __proto__: obj1 };

assert.notDeepEqual(obj1, obj1);
// AssertionError: { a: { b: 1 } } notDeepEqual { a: { b: 1 } }

assert.notDeepEqual(obj1, obj2);
// OK

assert.notDeepEqual(obj1, obj3);
// AssertionError: { a: { b: 1 } } notDeepEqual { a: { b: 1 } }

assert.notDeepEqual(obj1, obj4);
// OKcopy

如果这些值深度相等，则会抛出一个 AssertionError，其 message 属性设置为 message 参数的值。如果 message 参数未定义，则会分配一个默认错误消息。如果 message 参数是 <Error> 的实例，则会抛出它，而不是 AssertionError。

assert.notDeepStrictEqual(actual, expected[, message])#

• actual <any>
• expected <any>
• message <string> | <Error>

测试深度严格不相等。 与 assert.deepStrictEqual() 相反。

import assert from 'node:assert/strict';

assert.notDeepStrictEqual({ a: 1 }, { a: '1' });
// OKconst assert = require('node:assert/strict');

assert.notDeepStrictEqual({ a: 1 }, { a: '1' });
// OKcopy

如果这些值深度且严格相等，则会抛出一个 AssertionError，其 message 属性设置为 message 参数的值。如果 message 参数未定义，则会分配一个默认错误消息。如果 message 参数是 <Error> 的实例，则会抛出它，而不是 AssertionError。

assert.notEqual(actual, expected[, message])#

• actual <any>
• expected <any>
• message <string> | <Error>

严格断言模式

是 assert.notStrictEqual() 的别名。

旧式断言模式

使用 != 运算符测试浅层的、强制的非相等。 NaN 会被特殊处理，如果两边都是 NaN 则被认为是相同的。

import assert from 'node:assert';

assert.notEqual(1, 2);
// OK

assert.notEqual(1, 1);
// AssertionError: 1 != 1

assert.notEqual(1, '1');
// AssertionError: 1 != '1'const assert = require('node:assert');

assert.notEqual(1, 2);
// OK

assert.notEqual(1, 1);
// AssertionError: 1 != 1

assert.notEqual(1, '1');
// AssertionError: 1 != '1'copy

如果值相等，则会抛出一个 AssertionError，并且 message 属性设置为 message 参数的值。 如果 message 参数未定义，则会分配一个默认的错误消息。 如果 message 参数是 <Error> 的一个实例，那么它将被抛出，而不是抛出 AssertionError。

assert.notStrictEqual(actual, expected[, message])#

• actual <any>
• expected <any>
• message <string> | <Error>

测试 actual 和 expected 参数之间的严格不相等，由 Object.is() 确定。

import assert from 'node:assert/strict';

assert.notStrictEqual(1, 2);
// OK

assert.notStrictEqual(1, 1);
// AssertionError [ERR_ASSERTION]: Expected "actual" to be strictly unequal to:
//
// 1

assert.notStrictEqual(1, '1');
// OKconst assert = require('node:assert/strict');

assert.notStrictEqual(1, 2);
// OK

assert.notStrictEqual(1, 1);
// AssertionError [ERR_ASSERTION]: Expected "actual" to be strictly unequal to:
//
// 1

assert.notStrictEqual(1, '1');
// OKcopy

如果值严格相等，则会抛出一个 AssertionError，并且 message 属性设置为 message 参数的值。 如果 message 参数未定义，则会分配一个默认的错误消息。 如果 message 参数是 <Error> 的一个实例，那么它将被抛出，而不是抛出 AssertionError。

assert.ok(value[, message])#

• value <any>
• message <string> | <Error>

测试 value 是否为真值。 它等价于 assert.equal(!!value, true, message)。

如果 value 不是真值，则会抛出一个 AssertionError，并且 message 属性设置为 message 参数的值。 如果 message 参数是 undefined，则会分配一个默认的错误消息。 如果 message 参数是 <Error> 的一个实例，那么它将被抛出，而不是抛出 AssertionError。 如果根本没有传入参数，则 message 将被设置为字符串：'No value argument passed to `assert.ok()`'。

请注意，在 repl 中，错误消息将与在文件中抛出的错误消息不同！ 有关更多详细信息，请参见下文。

import assert from 'node:assert/strict';

assert.ok(true);
// OK
assert.ok(1);
// OK

assert.ok();
// AssertionError: No value argument passed to `assert.ok()`

assert.ok(false, 'it\'s false');
// AssertionError: it's false

// In the repl:
assert.ok(typeof 123 === 'string');
// AssertionError: false == true

// In a file (e.g. test.js):
assert.ok(typeof 123 === 'string');
// AssertionError: The expression evaluated to a falsy value:
//
//   assert.ok(typeof 123 === 'string')

assert.ok(false);
// AssertionError: The expression evaluated to a falsy value:
//
//   assert.ok(false)

assert.ok(0);
// AssertionError: The expression evaluated to a falsy value:
//
//   assert.ok(0)const assert = require('node:assert/strict');

assert.ok(true);
// OK
assert.ok(1);
// OK

assert.ok();
// AssertionError: No value argument passed to `assert.ok()`

assert.ok(false, 'it\'s false');
// AssertionError: it's false

// In the repl:
assert.ok(typeof 123 === 'string');
// AssertionError: false == true

// In a file (e.g. test.js):
assert.ok(typeof 123 === 'string');
// AssertionError: The expression evaluated to a falsy value:
//
//   assert.ok(typeof 123 === 'string')

assert.ok(false);
// AssertionError: The expression evaluated to a falsy value:
//
//   assert.ok(false)

assert.ok(0);
// AssertionError: The expression evaluated to a falsy value:
//
//   assert.ok(0)copy

import assert from 'node:assert/strict';

// Using `assert()` works the same:
assert(0);
// AssertionError: The expression evaluated to a falsy value:
//
//   assert(0)const assert = require('node:assert');

// Using `assert()` works the same:
assert(0);
// AssertionError: The expression evaluated to a falsy value:
//
//   assert(0)copy

assert.rejects(asyncFn[, error][, message])#

• asyncFn <Function> | <Promise>
• error <RegExp> | <Function> | <Object> | <Error>
• message <string>
• 返回: <Promise>

等待 asyncFn promise，或者如果 asyncFn 是一个函数，则立即调用该函数并等待返回的 promise 完成。 然后，它将检查 promise 是否被拒绝。

如果 asyncFn 是一个函数，并且它同步地抛出一个错误，那么 assert.rejects() 将返回一个被拒绝的 Promise，其中包含该错误。 如果该函数没有返回 promise，那么 assert.rejects() 将返回一个被拒绝的 Promise，其中包含一个 ERR_INVALID_RETURN_VALUE 错误。 在这两种情况下，都会跳过错误处理程序。

除了异步性质以等待完成之外，其行为与 assert.throws() 相同。

如果指定了 error，则它可以是一个 Class、 <RegExp>、一个验证函数、一个要测试其每个属性的对象，或者一个要测试其每个属性（包括不可枚举的 message 和 name 属性）的错误实例。

如果指定了 message，则当 asyncFn 未能拒绝时，它将是由 AssertionError 提供的消息。

import assert from 'node:assert/strict';

await assert.rejects(
  async () => {
    throw new TypeError('Wrong value');
  },
  {
    name: 'TypeError',
    message: 'Wrong value',
  },
);const assert = require('node:assert/strict');

(async () => {
  await assert.rejects(
    async () => {
      throw new TypeError('Wrong value');
    },
    {
      name: 'TypeError',
      message: 'Wrong value',
    },
  );
})();copy

import assert from 'node:assert/strict';

await assert.rejects(
  async () => {
    throw new TypeError('Wrong value');
  },
  (err) => {
    assert.strictEqual(err.name, 'TypeError');
    assert.strictEqual(err.message, 'Wrong value');
    return true;
  },
);const assert = require('node:assert/strict');

(async () => {
  await assert.rejects(
    async () => {
      throw new TypeError('Wrong value');
    },
    (err) => {
      assert.strictEqual(err.name, 'TypeError');
      assert.strictEqual(err.message, 'Wrong value');
      return true;
    },
  );
})();copy

import assert from 'node:assert/strict';

assert.rejects(
  Promise.reject(new Error('Wrong value')),
  Error,
).then(() => {
  // ...
});const assert = require('node:assert/strict');

assert.rejects(
  Promise.reject(new Error('Wrong value')),
  Error,
).then(() => {
  // ...
});copy

error 不能是一个字符串。 如果提供一个字符串作为第二个参数，那么 error 被假定为被省略，并且该字符串将用于代替 message。 这可能导致容易忽略的错误。 如果考虑使用一个字符串作为第二个参数，请仔细阅读 assert.throws() 中的示例。

assert.strictEqual(actual, expected[, message])#

• actual <any>
• expected <any>
• message <string> | <Error>

测试 actual 和 expected 参数之间的严格相等，由 Object.is() 确定。

import assert from 'node:assert/strict';

assert.strictEqual(1, 2);
// AssertionError [ERR_ASSERTION]: Expected inputs to be strictly equal:
//
// 1 !== 2

assert.strictEqual(1, 1);
// OK

assert.strictEqual('Hello foobar', 'Hello World!');
// AssertionError [ERR_ASSERTION]: Expected inputs to be strictly equal:
// + actual - expected
//
// + 'Hello foobar'
// - 'Hello World!'
//          ^

const apples = 1;
const oranges = 2;
assert.strictEqual(apples, oranges, `apples ${apples} !== oranges ${oranges}`);
// AssertionError [ERR_ASSERTION]: apples 1 !== oranges 2

assert.strictEqual(1, '1', new TypeError('Inputs are not identical'));
// TypeError: Inputs are not identicalconst assert = require('node:assert/strict');

assert.strictEqual(1, 2);
// AssertionError [ERR_ASSERTION]: Expected inputs to be strictly equal:
//
// 1 !== 2

assert.strictEqual(1, 1);
// OK

assert.strictEqual('Hello foobar', 'Hello World!');
// AssertionError [ERR_ASSERTION]: Expected inputs to be strictly equal:
// + actual - expected
//
// + 'Hello foobar'
// - 'Hello World!'
//          ^

const apples = 1;
const oranges = 2;
assert.strictEqual(apples, oranges, `apples ${apples} !== oranges ${oranges}`);
// AssertionError [ERR_ASSERTION]: apples 1 !== oranges 2

assert.strictEqual(1, '1', new TypeError('Inputs are not identical'));
// TypeError: Inputs are not identicalcopy

如果值不严格相等，则会抛出一个 AssertionError，并且 message 属性设置为 message 参数的值。 如果 message 参数未定义，则会分配一个默认的错误消息。 如果 message 参数是 <Error> 的一个实例，那么它将被抛出，而不是抛出 AssertionError。

assert.throws(fn[, error][, message])#

• fn <Function>
• error <RegExp> | <Function> | <Object> | <Error>
• message <string>

期望函数 fn 抛出一个错误。

如果指定了 error，则它可以是一个 Class、 <RegExp>、一个验证函数、一个要测试其每个属性的严格深度相等的验证对象，或者一个要测试其每个属性的严格深度相等（包括不可枚举的 message 和 name 属性）的错误实例。 当使用对象时，也可以使用正则表达式，当针对字符串属性进行验证时。 请参阅下面的示例。

如果指定了 message，则如果 fn 调用未能抛出错误或在错误验证失败的情况下，它将被附加到 AssertionError 提供的消息中。

自定义验证对象/错误实例

import assert from 'node:assert/strict';

const err = new TypeError('Wrong value');
err.code = 404;
err.foo = 'bar';
err.info = {
  nested: true,
  baz: 'text',
};
err.reg = /abc/i;

assert.throws(
  () => {
    throw err;
  },
  {
    name: 'TypeError',
    message: 'Wrong value',
    info: {
      nested: true,
      baz: 'text',
    },
    // Only properties on the validation object will be tested for.
    // Using nested objects requires all properties to be present. Otherwise
    // the validation is going to fail.
  },
);

// Using regular expressions to validate error properties:
assert.throws(
  () => {
    throw err;
  },
  {
    // The `name` and `message` properties are strings and using regular
    // expressions on those will match against the string. If they fail, an
    // error is thrown.
    name: /^TypeError$/,
    message: /Wrong/,
    foo: 'bar',
    info: {
      nested: true,
      // It is not possible to use regular expressions for nested properties!
      baz: 'text',
    },
    // The `reg` property contains a regular expression and only if the
    // validation object contains an identical regular expression, it is going
    // to pass.
    reg: /abc/i,
  },
);

// Fails due to the different `message` and `name` properties:
assert.throws(
  () => {
    const otherErr = new Error('Not found');
    // Copy all enumerable properties from `err` to `otherErr`.
    for (const [key, value] of Object.entries(err)) {
      otherErr[key] = value;
    }
    throw otherErr;
  },
  // The error's `message` and `name` properties will also be checked when using
  // an error as validation object.
  err,
);const assert = require('node:assert/strict');

const err = new TypeError('Wrong value');
err.code = 404;
err.foo = 'bar';
err.info = {
  nested: true,
  baz: 'text',
};
err.reg = /abc/i;

assert.throws(
  () => {
    throw err;
  },
  {
    name: 'TypeError',
    message: 'Wrong value',
    info: {
      nested: true,
      baz: 'text',
    },
    // Only properties on the validation object will be tested for.
    // Using nested objects requires all properties to be present. Otherwise
    // the validation is going to fail.
  },
);

// Using regular expressions to validate error properties:
assert.throws(
  () => {
    throw err;
  },
  {
    // The `name` and `message` properties are strings and using regular
    // expressions on those will match against the string. If they fail, an
    // error is thrown.
    name: /^TypeError$/,
    message: /Wrong/,
    foo: 'bar',
    info: {
      nested: true,
      // It is not possible to use regular expressions for nested properties!
      baz: 'text',
    },
    // The `reg` property contains a regular expression and only if the
    // validation object contains an identical regular expression, it is going
    // to pass.
    reg: /abc/i,
  },
);

// Fails due to the different `message` and `name` properties:
assert.throws(
  () => {
    const otherErr = new Error('Not found');
    // Copy all enumerable properties from `err` to `otherErr`.
    for (const [key, value] of Object.entries(err)) {
      otherErr[key] = value;
    }
    throw otherErr;
  },
  // The error's `message` and `name` properties will also be checked when using
  // an error as validation object.
  err,
);copy

使用构造函数验证 instanceof

import assert from 'node:assert/strict';

assert.throws(
  () => {
    throw new Error('Wrong value');
  },
  Error,
);const assert = require('node:assert/strict');

assert.throws(
  () => {
    throw new Error('Wrong value');
  },
  Error,
);copy

使用 <RegExp> 验证错误消息

使用正则表达式对错误对象运行 .toString，因此也会包含错误名称。

import assert from 'node:assert/strict';

assert.throws(
  () => {
    throw new Error('Wrong value');
  },
  /^Error: Wrong value$/,
);const assert = require('node:assert/strict');

assert.throws(
  () => {
    throw new Error('Wrong value');
  },
  /^Error: Wrong value$/,
);copy

自定义错误验证

该函数必须返回 true 以指示所有内部验证都已通过。 否则，它将失败并显示 AssertionError。

import assert from 'node:assert/strict';

assert.throws(
  () => {
    throw new Error('Wrong value');
  },
  (err) => {
    assert(err instanceof Error);
    assert(/value/.test(err));
    // Avoid returning anything from validation functions besides `true`.
    // Otherwise, it's not clear what part of the validation failed. Instead,
    // throw an error about the specific validation that failed (as done in this
    // example) and add as much helpful debugging information to that error as
    // possible.
    return true;
  },
  'unexpected error',
);const assert = require('node:assert/strict');

assert.throws(
  () => {
    throw new Error('Wrong value');
  },
  (err) => {
    assert(err instanceof Error);
    assert(/value/.test(err));
    // Avoid returning anything from validation functions besides `true`.
    // Otherwise, it's not clear what part of the validation failed. Instead,
    // throw an error about the specific validation that failed (as done in this
    // example) and add as much helpful debugging information to that error as
    // possible.
    return true;
  },
  'unexpected error',
);copy

error 不能是一个字符串。 如果提供一个字符串作为第二个参数，那么 error 被假定为被省略，并且该字符串将用于代替 message。 这可能导致容易忽略的错误。 使用与抛出的错误消息相同的消息将导致 ERR_AMBIGUOUS_ARGUMENT 错误。 如果考虑使用一个字符串作为第二个参数，请仔细阅读下面的示例

import assert from 'node:assert/strict';

function throwingFirst() {
  throw new Error('First');
}

function throwingSecond() {
  throw new Error('Second');
}

function notThrowing() {}

// The second argument is a string and the input function threw an Error.
// The first case will not throw as it does not match for the error message
// thrown by the input function!
assert.throws(throwingFirst, 'Second');
// In the next example the message has no benefit over the message from the
// error and since it is not clear if the user intended to actually match
// against the error message, Node.js throws an `ERR_AMBIGUOUS_ARGUMENT` error.
assert.throws(throwingSecond, 'Second');
// TypeError [ERR_AMBIGUOUS_ARGUMENT]

// The string is only used (as message) in case the function does not throw:
assert.throws(notThrowing, 'Second');
// AssertionError [ERR_ASSERTION]: Missing expected exception: Second

// If it was intended to match for the error message do this instead:
// It does not throw because the error messages match.
assert.throws(throwingSecond, /Second$/);

// If the error message does not match, an AssertionError is thrown.
assert.throws(throwingFirst, /Second$/);
// AssertionError [ERR_ASSERTION]const assert = require('node:assert/strict');

function throwingFirst() {
  throw new Error('First');
}

function throwingSecond() {
  throw new Error('Second');
}

function notThrowing() {}

// The second argument is a string and the input function threw an Error.
// The first case will not throw as it does not match for the error message
// thrown by the input function!
assert.throws(throwingFirst, 'Second');
// In the next example the message has no benefit over the message from the
// error and since it is not clear if the user intended to actually match
// against the error message, Node.js throws an `ERR_AMBIGUOUS_ARGUMENT` error.
assert.throws(throwingSecond, 'Second');
// TypeError [ERR_AMBIGUOUS_ARGUMENT]

// The string is only used (as message) in case the function does not throw:
assert.throws(notThrowing, 'Second');
// AssertionError [ERR_ASSERTION]: Missing expected exception: Second

// If it was intended to match for the error message do this instead:
// It does not throw because the error messages match.
assert.throws(throwingSecond, /Second$/);

// If the error message does not match, an AssertionError is thrown.
assert.throws(throwingFirst, /Second$/);
// AssertionError [ERR_ASSERTION]copy

由于令人困惑的容易出错的表示法，请避免使用字符串作为第二个参数。

assert.partialDeepStrictEqual(actual, expected[, message])#

• actual <any>
• expected <any>
• message <string> | <Error>

测试 actual 和 expected 参数之间的部分深度相等。“深度”相等意味着子对象的可枚举“自有”属性也通过以下规则以递归方式进行评估。“部分”相等意味着仅将比较 expected 参数上存在的属性。

此方法始终通过与 assert.deepStrictEqual() 相同的测试用例，其行为就像它的超集。

import assert from 'node:assert';

assert.partialDeepStrictEqual(
  { a: { b: { c: 1 } } },
  { a: { b: { c: 1 } } },
);
// OK

assert.partialDeepStrictEqual(
  { a: 1, b: 2, c: 3 },
  { b: 2 },
);
// OK

assert.partialDeepStrictEqual(
  [1, 2, 3, 4, 5, 6, 7, 8, 9],
  [4, 5, 8],
);
// OK

assert.partialDeepStrictEqual(
  new Set([{ a: 1 }, { b: 1 }]),
  new Set([{ a: 1 }]),
);
// OK

assert.partialDeepStrictEqual(
  new Map([['key1', 'value1'], ['key2', 'value2']]),
  new Map([['key2', 'value2']]),
);
// OK

assert.partialDeepStrictEqual(123n, 123n);
// OK

assert.partialDeepStrictEqual(
  [1, 2, 3, 4, 5, 6, 7, 8, 9],
  [5, 4, 8],
);
// AssertionError

assert.partialDeepStrictEqual(
  { a: 1 },
  { a: 1, b: 2 },
);
// AssertionError

assert.partialDeepStrictEqual(
  { a: { b: 2 } },
  { a: { b: '2' } },
);
// AssertionErrorconst assert = require('node:assert');

assert.partialDeepStrictEqual(
  { a: { b: { c: 1 } } },
  { a: { b: { c: 1 } } },
);
// OK

assert.partialDeepStrictEqual(
  { a: 1, b: 2, c: 3 },
  { b: 2 },
);
// OK

assert.partialDeepStrictEqual(
  [1, 2, 3, 4, 5, 6, 7, 8, 9],
  [4, 5, 8],
);
// OK

assert.partialDeepStrictEqual(
  new Set([{ a: 1 }, { b: 1 }]),
  new Set([{ a: 1 }]),
);
// OK

assert.partialDeepStrictEqual(
  new Map([['key1', 'value1'], ['key2', 'value2']]),
  new Map([['key2', 'value2']]),
);
// OK

assert.partialDeepStrictEqual(123n, 123n);
// OK

assert.partialDeepStrictEqual(
  [1, 2, 3, 4, 5, 6, 7, 8, 9],
  [5, 4, 8],
);
// AssertionError

assert.partialDeepStrictEqual(
  { a: 1 },
  { a: 1, b: 2 },
);
// AssertionError

assert.partialDeepStrictEqual(
  { a: { b: 2 } },
  { a: { b: '2' } },
);
// AssertionErrorcopy