lodash - isEqual ignore undefined

Question

How can I use lodash to deep check the equality of two objects, ignoring undefined.

i.e.

const a = { a: 1, b: 2 };
const b = { a: 1 };

_.isEqual(a, b); // => true

user_5157454 · Answer

You can use _.isMatch() which performs a partial deep comparison between object (a) and source (b) to determine if object contains equivalent property values to source.

const a = { a: 1, b: 2 };
const b = { a: 1 };

console.log(_.isEqual(a, b)); // false
console.log(_.isMatch(a, b)); // true
console.log(_.isMatch(b, a)); // false

This would only work if a key doesn't exist on the source. If a key exist with an explicit value of undefined, the result would be false.

const a = { a: 1, b: 2 };
const b = { a: 1, c: undefined };

console.log(_.isMatch(a, b)); // false

lodash - isEqual ignore undefined

1 Answers