| # | title | topic | type | difficulty |
|---|---|---|---|---|
| 61 | Function composition — approach 2: a plain loop | Arrays | Coding | Medium |
| 62 | Make c == 1 && c == 2 && c == 3 true | Type Coercion | Coding | Hard |
| 63 | The closure-in-a-loop bug, as code | YDKJS Book | Coding | Hard |
| 64 | createSpy — the test-double HOF | YDKJS Book | Coding | Hard |
| 65 | Multi-argument memoize (a Map trie) |
| YDKJS Book |
| Coding |
| Hard |
| 66 | Breadth-first search: shortest path | Algorithms & Recursion | Coding | Hard |
| 67 | Depth-first search: recursive traversal | Algorithms & Recursion | Coding | Medium |
| 68 | Binary search (and where to insert) | Algorithms & Recursion | Coding | Hard |
| 69 | Head recursion vs tail recursion | Algorithms & Recursion | Coding | Hard |
| 70 | Insane Fibonacci: fib(78), recursively, in 2 seconds | Algorithms & Recursion | Coding | Hard |
| 71 | Insane FizzBuzz: no if, no ternary, no switch | Algorithms & Recursion | Coding | Hard |
| 72 | Double every number | Arrays | Coding | Easy |
| 73 | Keep only the evens | Arrays | Coding | Easy |
| 74 | First negative number | Arrays | Coding | Easy |
| 75 | Make a CSV line | Arrays | Coding | Easy |
| 76 | Clamp a number to a range | Math | Coding | Easy |
| 77 | Pull values out with destructuring | Destructuring | Coding | Easy |
| 78 | Count an object's keys | Objects | Coding | Easy |
| 79 | Merge in defaults with spread | Objects | Coding | Easy |
| 80 | Sum 1 to n with a for loop | Loops | Coding | Easy |
| 81 | Countdown with while | Loops | Coding | Easy |
| 82 | Extract the hostname | URL & Web APIs | Coding | Easy |
| 83 | Format a price with toFixed | Floating Point | Coding | Easy |
| 84 | Dollars to cents, safely | Payments | Coding | Easy |
| 85 | Sort numbers correctly | Sorting Algorithms | Coding | Easy |
| 86 | Reverse a string | Interview Classics | Coding | Easy |
| 87 | Palindrome check | Interview Classics | Coding | Easy |
| 88 | FizzBuzz, the classic | Algorithms & Recursion | Coding | Easy |
| 89 | Kill the O(n²) lookup | Patterns & Performance | Coding | Medium |
| 90 | Order-preserving dedupe at scale | Patterns & Performance | Coding | Hard |