JavaScript Basics Cheat Sheet

Variables

let name = "John";
const age = 30;
var oldWay = "deprecated";

Data Types

let str = "string";
let num = 42;
let bool = true;
let arr = [1, 2, 3];
let obj = { key: "value" };

Operators

+, -, *, /, %
===, !==, <, >, <=, >=
&&, ||, !
typeof variable