rejects
Awaits the asyncFn
promise or, if asyncFn
is a function, immediately calls the function and awaits the returned promise to complete. It will then check that the promise is rejected.
If asyncFn
is a function and it throws an error synchronously, assert.rejects()
will return a rejected Promise
with that error. If the function does not return a promise, assert.rejects()
will return a rejected Promise
with an ERR_INVALID_RETURN_VALUE error. In both cases the error handler is skipped.
Besides the async nature to await the completion behaves identically to {@link throws}.
If specified, error
can be a Class
, RegExp
, a validation function, an object where each property will be tested for, or an instance of error where each property will be tested for including the non-enumerable message
and name
properties.
If specified, message
will be the message provided by the {@link AssertionError}
if the asyncFn
fails to reject.
import assert from 'node:assert/strict';
await assert.rejects(
async () => {
throw new TypeError('Wrong value');
},
{
name: 'TypeError',
message: 'Wrong value',
},
);
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;
},
);
import assert from 'node:assert/strict';
assert.rejects(
Promise.reject(new Error('Wrong value')),
Error,
).then(() => {
// ...
});
error
cannot be a string. If a string is provided as the second argument, then error
is assumed to be omitted and the string will be used for message
instead. This can lead to easy-to-miss mistakes. Please read the example in {@link throws} carefully if using a string as the second argument gets considered.
Since
v10.0.0