Learn the algorithms with the language you already write every day.
Every example is a complete Node.js program with no framework, no npm packages and no TypeScript. The book covers the classic data structures and algorithms, and the JavaScript details that trip people up in interviews and real code: references, UTF-16 strings, number precision and the hidden cost of some array methods.
Choose between arrays, Map and Set by what you need to look up, and avoid objects as accidental hash tables.
See why indexing a string can split an emoji in half, and how to loop over characters safely.
Understand when two variables point at the same object, the root of many linked-structure bugs.
Why repeated shift() makes a queue slow, and when a Number is not precise enough for a sum.
Each chapter has a complete program to run, the time and memory cost, and exercises.
Set up a current LTS release of Node.js, an editor and a terminal.
The reliable core: values, variables, functions, loops, arrays and comparisons.
The everyday storage tools, and how to choose among them.
Why string indexes are UTF-16 code units, and how to handle characters correctly.
Group fields into nodes and records, and reason about shared, mutable objects.
Base cases, smaller instances, and the stack space every call uses.
The two ordering rules behind DFS, BFS, bracket checking and scheduling.
Nodes joined by references, and the cost of reaching an element.
Find a value by key without scanning, using Map for counting and membership.
Traverse a tree, insert and search a BST, and see why “binary” does not mean fast.
Serve the most urgent item first with a compact binary heap.
Linear and binary search, a predictable merge sort, and JavaScript’s default sort trap.
Reuse work across an array, with half-open ranges and safe sums.
Combine answers to subproblems, or explore and undo choices.
Represent a graph with Map and Set, run BFS and DFS, and recover a shortest path.
Prove when a locally attractive choice is globally optimal.
Turn repeated subproblems into a table with explicit states and transitions.
Choose a technique without a chapter title to help, and build a small dependency planner.
Debugging Is the Skill teaches a method for finding the bug instead of resubmitting, with sixteen planted bugs to practise on.
Explore the debugging book