18Implement a basic `deepEqual()` for nested arrays and objects

easyAbout 15 minutesCodingrecursionobjectsarrays

Problem

Implement deepEqual(a, b). It returns true when two values have the same structure and the same primitive values, however deeply nested.

deepEqual({ a: [1, { b: 2 }] }, { a: [1, { b: 2 }] }); // true
deepEqual([1, 2], [2, 1]); // false
deepEqual({ a: 1 }, { a: 1, b: 2 }); // false

Requirements

Handle primitives, arrays and plain objects, nested to any depth.
Arrays are equal only when they have the same items in the same order.
Objects are equal when they have the same own keys with deeply equal values, in any key order.
An array is never equal to an object, even one with the same keys.
NaN equals NaN.

Write your solution, run it, then submit to check it against the tests.

solution.jsJavaScript

Runs in your browser. Saved on this device.

Press Run or ⌘ Enter to execute your code.

If a === b, they are equal (same primitive or same reference). If both are NaN, they are equal too, even though NaN === NaN is false.

What's inside

Includes 2 code listings, 5 edge cases, 4 follow-up questions.

One-time payment by UPI, card or net banking. Launch price.