What is “assert” in JavaScript?

Question

What does assert mean in JavaScript?

I’ve seen something like:

assert(function1() && function2() && function3(), \"some          


        

Answer 1

The other answers are good: there isn't an assert function built into ECMAScript5 (e.g. JavaScript that works basically everywhere) but some browsers give it to you or have add-ons that provide that functionality. While it's probably best to use a well-established / popular / maintained library for this, for academic purposes a "poor man's assert" function might look something like this:

const assert = function(condition, message) {
    if (!condition)
        throw Error('Assert failed: ' + (message || ''));
};

assert(1 === 1); // Executes without problem
assert(false, 'Expected true');
// Yields 'Error: Assert failed: Expected true' in console