Javascript Weird Parts [upd] Guide

If you’ve spent more than 48 hours with JavaScript, you’ve probably uttered the phrase: “Wait… why did it do that?”

console.log(0.1 + 0.2); // 0.30000000000000004 console.log(0.1 + 0.2 === 0.3); // false Floating-point math. JavaScript uses binary floating point; 0.1 in binary is a repeating fraction (like 1/3 in decimal). It can't be represented exactly. javascript weird parts

function show() { console.log(this); } show(); // window (or global in Node) new show(); // {} (the new instance) If you’ve spent more than 48 hours with

Arrow functions don't have their own this —they inherit from the parent scope. That’s often a lifesaver, but it’s another thing to memorize. Every value in JS is inherently truthy or falsy. There are exactly 8 falsy values : javascript weird parts