Data structures and algorithms in JavaScript: Big O, stacks, queues, linked lists, searching, and sorting.
You can already write JavaScript that works. This course is about the next question: what does it cost, and could it cost less? Data structures are the shapes information lives in, stacks, queues, and chains. Algorithms are the recipes that work on them, searching, sorting, and scanning. Together they are how engineers reason about code, and they are what technical interviews are actually testing.
The subject has a frightening reputation, so this course is built deliberately small: ten sections, one idea per lesson, and a concrete picture for every structure. A stack is a pile of plates. A queue is the line at a shop. A linked list is a treasure hunt where each clue names the next hiding place. You never take a claim about speed on faith, because you count the steps yourself and read the number. Fast and slow stop being opinions and become measurements you made.
Everything happens in one place: the Mixtape, a six-track playlist. Every section rebuilds part of it with the structure that section teaches, so the editor is never blank and your attention goes to the new idea. You ship four programs from it, a play report built on lookup tables, an undo feature built on a stack, the playlist rebuilt as a chain, and the Mixtape Engine capstone, where the right structure and the right algorithm run together. Finish everything and your certificate is waiting.
60 Lessons • 62 Practices • 21 Quizzes • 4 Projects · ~12h Total
Not just theory. You finish this course with real work to show.
This is the same in-browser editor every lesson uses. Edit the code, hit Run.
Run code in the browser and see the result immediately. Every lesson works this way.
Stuck? Puff explains the error and nudges you forward, without giving the answer away.
Streaks, diamonds, and certificates. Your progress saves automatically, forever.
Every completed course issues a certificate with a public verification link.
Every certificate has a public verification link employers can check.
One certificate per course. Finish a program and earn its program certificate too.
LinkedIn-ready, with a PDF you can download and attach.
You have the tools and your code works. This course teaches the thinking that decides which tool to reach for.
Big O, stacks, queues, linked lists, and binary search are the interview. Learn them gently, once, properly.
You build things that work and suspect there are gaps where a computer science course would have been. These are the gaps.
DSA Basics is free to start, no credit card needed. Some later sections are part of Pro, and finishing every section, including the certificate, needs a Pro plan.
Yes, or its ground: loops, functions, arrays, objects, array methods, callbacks, and classes. Sections 6, 7, and 8 build a Stack, a Queue, and a Node as classes, so the class syntax needs to be familiar rather than new. If you can write a class with a constructor and a method without looking it up, you are ready.
It is the half that comes first. Big O, arrays, hash lookups, stacks, queues, linked lists, binary search, and sorting are the material most technical interviews draw from, and this course teaches all of them. Trees, graphs, and dynamic programming are the other half, and they have their own course, Advanced DSA. Interview practice itself is repetition against a question bank; this course is the material that makes the repetition worth doing.
Because it would lie to you. A browser runs a hundred million operations in about a quarter of a second, so on any list small enough to fit in a lesson, the slow solution and the fast one both finish instantly. Timing would teach you that everything is fast. Counting operations tells the truth at any size, so every measurement in this course is a counter you increment yourself and a number you read.
No. Big O in practice is counting and naming shapes, not algebra. If you can count how many times a loop runs and notice that doubling the list doubled the count, you have the whole idea. There are no proofs, no limits, and no summation notation anywhere in this course.
Four programs from one six-track playlist: a play report that replaces a nested loop with a lookup table, an undo feature built on a stack you write yourself, the playlist rebuilt as a linked list, and the Mixtape Engine capstone, where you choose the structure and the algorithm rather than being told which to use.
Yes, two of them. Finish every item in DSA Basics and Devpuff issues a course certificate with a public link that anyone can verify. DSA Basics is also part of the Frontend Development program, so finishing every course in that program issues a program certificate as well.
How this course connects to the bigger picture, and what to explore next.
Handle time and the network: promises, async and await, JSON, fetch, and requests that fail.
Level up your JavaScript: arrow functions, array methods, destructuring, spread, classes, and errors.
Write real web pages by hand: document structure, text, links, lists, images, semantic HTML, and forms.
Free to start, no credit card required. Write real code from the first lesson and keep your progress forever.
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