JavaScript Const vs. Var vs. Let: A Comprehensive Guide for All Time

javascript October 22, 2021

JavaScript in Plain English, a Medium blog, has an interesting article called “JavaScript Const vs. Var vs. Let: A Comprehensive Guide for All Time”, which… as it says on the tin, walks through a fairly comprehensive discussion of javascript’s var, let, and const keywords, and when to use them.

Along the way, it talks about “hoisting” - the mechanism where JavaScript will reorder your code at runtime - and the impact that has on your code, and how to manage variable declarations with proper scope.

The rules seem fairly simple, though: use let if the reference is mutable, use const if it is not, and use var if you don’t care about your fellow coders much. (This is a really poor summary, obviously, and JavaScript’s const declarations are much like Java’s final declarations and C’s const as well - the reference is immutable, but the thing it points to might not be.)

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