Javascript
Understanding JavaScript Promises: Chaining, Error Handling, and async/await
A practical guide to working with JavaScript Promises - from basic chaining and resolve/reject behavior to .catch, Promise.all fail-fast handling, and async/await error patterns.
JavaScript Closures: Lexical Scope and the Environment That Survives Function Return
A closure is a function bundled with the lexical environment it was created in. That environment survives because the closure holds a reference to it - which is why each call to a function factory returns an independent counter.
JavaScript Prototypal Inheritance: The Prototype Chain, `new`, and Class Syntax
How JavaScript actually shares methods between objects - the prototype chain, what `new` really does, and how ES6 class syntax maps onto the same underlying machinery.
How JavaScript `this` Works: Function Invocation and the `.call` Primitive
A single-rule mental model for JavaScript's `this` - everything desugars to `Function.prototype.call(thisValue, ...args)`. Walks through bare calls, method calls, detachment, `.call` / `.apply` / `.bind`, the `new` operator, arrow functions, strict mode, and how to implement `.bind` from scratch.