What is “assert” in JavaScript?

Question

What does assert mean in JavaScript?

I’ve seen something like:

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


        

Answer 1

As mentioned by T.J., There is no assert in JavaScript. However, there is a node module named assert, which is used mostly for testing. so, you might see code like:

const assert = require('assert');
assert(5 > 7);

Answer 2

In addition to other options like console.assert or rolling your own, you can use invariant. It has a couple of unique features:

• It supports formatted error messages (using a %s specifier).
• In production environments (as determined by the Node.js or Webpack environment), the error message is optional, allowing for (slightly) smaller .js.