What Is JavaScript’s Strict Mode?

Strict mode in JavaScript tightens the rules for certain behaviors. Here's everything you need to know about it.

JavaScript is a forgiving language. Some of its syntaxes is optional, and the language recovers from errors with more grace than many others. But this hand-holding comes with a penalty: it can be easier to introduce bugs, and inconsistent code is harder to read.

Fortunately, if you want to exercise more discipline, there’s an easy way of doing so: strict mode. Strict mode is a way of asking JavaScript to react more decisively when it encounters problems in your code.