“use strict” mode in JavaScript

What does “use strict” do in JavaScript, and what is the reasoning behind it?

Last updated:7/20/2021 1:42:24 AM

1 Answers

Ethan Karla
Ethan Karla

Strict mode was a new feature in ECMAScript 5 that allows you to place a program or function in a 'strict' operating context. This strict reference prevents certain actions from happening and throwing more exceptions. statement 'use strict'; Instructs the browser to use strict mode, which is a less secure feature set of JavaScript.

Benefits of using strict: Strict mode introduces many changes to normal JavaScript semantics.

Strict mode eliminates some JavaScript silent errors by turning them into throw errors.

Strict mode fixes mistakes that make it difficult for JavaScript engines to optimize: Strict mode code can sometimes be made to run faster than similar code that is not strict mode.

Strict mode restricts some of the syntax to be defined in future versions of ECMAScript.

It prevents, or throws, errors when relatively 'unsafe' actions are performed (such as accessing a global object).

It disables features that are confusing or poorly thought out.

Strict mode makes it easy to write 'safe' JavaScript.

How to use strict mode: Strict mode can be used in two ways, remember that strict mode does not work with block statements enclosed in {} braces.

Used in the global scope for the entire script.

It can be applied to individual tasks.