doesNotThrow

Asserts that the function fn does not throw an error.

Using assert.doesNotThrow() is actually not useful because there is no benefit in catching an error and then rethrowing it. Instead, consider adding a comment next to the specific code path that should not throw and keep error messages as expressive as possible.

When assert.doesNotThrow() is called, it will immediately call the fn function.

If an error is thrown and it is the same type as that specified by the error parameter, then an AssertionError is thrown. If the error is of a different type, or if the error parameter is undefined, the error is propagated back to the caller.

If specified, error can be a Class, RegExp, or a validation function. See {@link throws} for more details.

The following, for instance, will throw the TypeError because there is no matching error type in the assertion:

import assert from 'node:assert/strict';

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

However, the following will result in an AssertionError with the message 'Got unwanted exception...':

import assert from 'node:assert/strict';

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

If an AssertionError is thrown and a value is provided for the message parameter, the value of message will be appended to the AssertionError message:

import assert from 'node:assert/strict';

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