Understanding how string methods work under the hood — and building them yourself. Here's something that changed how I think about JavaScript: anyone can use .trim() or .includes() . You call the method, it works, you move on. But can you build it from scratch? Can you explain what happens inside when you call .split() or .repeat() ? That's exactly what interviewers want to know. Not whether you've memorized the API, but whether you understand the logic behind it. And the best way to prove that? Write the method yourself — a polyfill . In the ChaiCode Web Dev Cohort 2026, this shift from "using tools" to "understanding tools" was a turning point. Let me walk you through the most common string methods, how they work conceptually, and how to build your own versions. What Are String Methods? String methods are built-in functions that every string in JavaScript comes with. They let you manipulate, search, transform, and inspect text without writing manual loops. const name = " Pratham Bhardwaj " ; console .…