beginner
9 min read
Arrays and Objects Basics
A variable can hold one value—and that value can be a collection holding many related values. JavaScript arrays and objects are how you build those…
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JavaScript Data Structures
Organizing, accessing, transforming, and representing collections and structured data in JavaScript.
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JavaScript Data Structures articles
16 articles in this tag.
beginner
13 min read
Build a JavaScript Quiz App
You've learned arrays, conditionals, click events, and DOM updates as separate lessons. Now it's time to see them work together. A quiz app is the perfect…
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beginner
14 min read
Build a Searchable List with JavaScript
Every product you use has one: a search box that narrows a list as you type. Contact lists, product catalogs, dashboards, admin panels—they all use the…
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beginner
14 min read
Build an Image Slider with JavaScript
An image slider looks like a piece of fancy UI magic. Underneath, it is just a number moving through an array and telling the page which image to show.…
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beginner
10 min read
Create a Random Quote Generator
Click a button. Watch the page change. That small moment—where your JavaScript stops just running and starts doing something visible—is the bridge between…
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beginner
7 min read
Fix "Assignment to Constant Variable" in JavaScript
Now you're stuck on a question that feels bigger than the error itself: do you change the const to let, or do you rewrite the line that's failing? The…
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beginner
12 min read
JavaScript Array Methods: map, filter, and reduce
You know how to build an array. Now comes the part where every beginner hits the same wall: you need to change the values, keep only some of them, or total…
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beginner
11 min read
JavaScript Destructuring and Spread Syntax for Arrays and Objects
Three lines, three property reads, three variables. It works, and it is honest code. But then you see a modern codebase do the same job in one line, with…
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beginner
10 min read
Work with JSON in JavaScript: Parse and Stringify Data
You log a value from an API or from localStorage, and it looks exactly like an object. You can see the keys. You can see the values. So you try to read a…
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beginner
9 min read
for Loops vs forEach vs map in JavaScript
You can loop over an array three different ways, and they all look nearly identical when you write them. So which one should you use?
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beginner
7 min read
JavaScript Object Methods and this: Use Data Inside a Method
You copy a method into a new variable, call it, and get undefined instead of the name you expected. Nothing in the object changed. Nothing in the function…
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beginner
10 min read
JavaScript Set and Map: When to Use Each Collection
You have a list of tags with duplicates, or you want to count visits per user object, and your array or plain object starts fighting you. Here are the two…
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beginner
12 min read
Make a Simple To-Do List
A to-do list is the first app where your page stops being a static document and starts remembering what the user does. Same event-listening idea as a click…
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beginner
11 min read
Model Application Data with JavaScript Objects
You have probably already written code like this: a cartTotal here, a userName there, an isLoggedIn flag somewhere else. It works, right up until you…
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beginner
10 min read
Next Steps in JavaScript
You finished the basics. You built a calculator, a to-do list, and maybe a number guessing game. The code runs. The buttons work. And now the map runs out.
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beginner
8 min read
Render an Array as a List in the DOM
You have an array of names sitting in your JavaScript file. You want those names to show up as bullet points on the page. The naive approach is to write…
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