Why is it possible to declare variable named let when I can't declare const or var. I know I will never do that , but I am just curious if there is reasonable explanation. So I can do:
var let = 5;
let x = 3;
x + let -> 8
Why is this even possible?
From the Mozilla Developer Network site under Future reserved keywords:
The following are only reserved when they are found in strict mode code:
which includes let.
However, const and var are listed under Reserved keywords as of ECMAScript 6 and this document shows the history where they were originally reserved in ECMAScript 1.
To invoke strict mode for an entire script, put the exact statement
"use strict";(or'use strict';) before any other statements.
What is strict mode?
ECMAScript 5's strict mode is a way to opt in to a restricted variant of JavaScript. Strict mode isn't just a subset: it intentionally has different semantics from normal code. Browsers not supporting strict mode will run strict mode code with different behavior from browsers that do
i think you can still write this in browser's console because the lately support ES6 and let may still not blocked to be defined.
