function assert.ok
Usage in Deno
import assert from "node:assert";
ok(value: unknown,message?: string | Error,): asserts value
Tests if value
is truthy. It is equivalent to assert.equal(!!value, true, message)
.
If value
is not truthy, an AssertionError
is thrown with a message
property set equal to the value of the message
parameter. If the message
parameter is undefined
, a default
error message is assigned. If the message
parameter is an instance of an Error
then it will be thrown instead of the AssertionError
.
If no arguments are passed in at all message
will be set to the string:'No value argument passed to `assert.ok()`'
.
Be aware that in the repl
the error message will be different to the one
thrown in a file! See below for further details.
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)
import assert from 'node:assert/strict';
// Using `assert()` works the same:
assert(0);
// AssertionError: The expression evaluated to a falsy value:
//
// assert(0)
asserts value