assert.ifError(value)

版本历史
版本变更
v10.0.0

其现在被封装到包含完整堆栈跟踪的 [AssertionError][] 中，而不是抛出原始错误。

v10.0.0

值现在可能仅为 undefined 或 null。 之前所有的假值都与 null 一样处理并且没有抛出错误。

v0.1.97

新增于: v0.1.97

如果 value 不是 undefined 或 null，则抛出 value。 这在回调中测试 error 参数时很有用。 堆栈跟踪包含来自传给 ifError() 的错误的所有帧，包括 ifError() 本身的潜在新帧。

const assert = require('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

// 创建一些随机错误帧。
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 errorFrame
History
VersionChanges
v10.0.0

Instead of throwing the original error it is now wrapped into an [AssertionError][] that contains the full stack trace.

v10.0.0

Value may now only be undefined or null. Before all falsy values were handled the same as null and did not throw.

v0.1.97

Added in: v0.1.97

Throws value if value is not undefined or null. This is useful when testing the error argument in callbacks. The stack trace contains all frames from the error passed to ifError() including the potential new frames for ifError() itself.

const assert = require('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 errorFrame