JavaScript Debugging with assertions - console.assert()


Writes an error message to the console if the assertion is false. Otherwise, if the assertion is true, this does nothing.

console.assert('one' === 1);


Multiple arguments can be provided after the assertion–these can be strings or other objects–that will only be printed if the assertion is false:

Assertion with multiple objects as parameters

console.assert does not throw an AssertionError (except in Node.js), meaning that this method is incompatible with most testing frameworks and that code execution will not break on a failed assertion.