Node.js assert.ok() Method

If an expression evaluates to 0 or false, an error is thrown and the program is terminated:

var assert = require('assert');
assert.ok(50 > 70);

Definition and Usage

The assert.ok() method tests if a given expression is true or not.

If the expression evaluates to 0, or false, an assertion failure is being caused, and the program is terminated.

assert.ok(expression, message);

Parameter	Description
expression	Required. Specifies an expression to be evaluated
message	Optional. Specifies the error message to be assigned to the AssertionError. If omitted, a default message is assigned

Return Value:	None
Node.js Version:	0.1.21

Using the message parameter:

var assert = require('assert');
assert.ok(50 > 70, "My message goes here");

The assert.ok() method also throws an error if the expression evaluates to 0:

var assert = require('assert');
assert.ok(50 - 50);