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JavaScript functions do not all decide this the same way. Regular functions usually get this from how they are called. Arrow functions do not create their own this at all. This post is about two questions: Where does a …
Closures show up any time a JavaScript function uses a variable defined from outside its own curly braces. That makes them common in callbacks, event handlers, timers, factory functions, and plenty of code that passes …
Hoisting is JavaScript’s setup behavior for declarations. It affects whether a function or variable can be used before the line where it appears in the file. That matters because function, var, let, and const do …
Most JavaScript code starts with a simple act: you give a value a name. We call that a variable declaration. That sounds small, but the way you create that name affects how the rest of your code can use it. A variable …
A Promise is a guaranteed placeholder value for what a function or series of functions will return. It’s a promise to return a value eventually. The function swears this time is different. You can trust it. It …
I ran into this error while using Rollup and the uuid package: Error: Crypto.getRandomValues() not supported. See https://github.com/uuidjs/uuid#getrandomvalues-not-supported The problem? It boiled down to this small …
The JavaScript spread ... syntax is amazing. What it does is let you take the individual items from an array, or the individual properties from an object, and spread them out into another place. That “another …
Brief History of Callbacks It all starts with the callback function. A callback function is just a plain JavaScript function that is passed into another function as an argument. That’s it. Nothing special. This …
JavaScript Function Signatures Alright, you’ve probably seen functions before. Something like this maybe? function doSomething(name, desc, task) { // did something } This function, named doSomething, takes three …
