What is the best way to ascertain the variance between two Immutable.js Maps?

Question

What is the best way to ascertain the variance between two Immutable.js Maps?

I currently have two unchangeable maps:

const initial_map = Map({x: 10, y: 20)}
const updated_map = Map({x: 15, y: 20)}

Can anyone advise on how to find the changes between the two maps? The expected outcome should be:

Map({x: 15})

javascript immutable.js

Answer 1

Answer №1

One way to approach this is by utilizing the Map.filter() function, also known as Collection.Keyed.filter(), on the second map with a specific condition: each element in this Map should not have a matching key in the other Map. Here's an example:

const Map = Immutable.Map;

const first_map = Map({a: 1, b: 2, c: 4});
const second_map = Map({a: 1, b: 3, d: 5});

const diff = second_map.filter((v, k) => first_map.get(k) !== v);

console.log(diff.toString()); // Map { "b": 3, "d": 5 }

<script src="https://cdnjs.cloudflare.com/ajax/libs/immutable/3.8.2/immutable.min.js"></script>

In cases where there might be undefined values in the Map, it's recommended to first check using has, as Map.get(key) will return undefined for non-existent keys. However, using null instead of undefined is preferable for clarity and consistency.

Answer 2

One way to approach this is by utilizing the Map.filter() function, also known as Collection.Keyed.filter(), on the second map with a specific condition: each element in this Map should not have a matching key in the other Map. Here's an example:

const Map = Immutable.Map;

const first_map = Map({a: 1, b: 2, c: 4});
const second_map = Map({a: 1, b: 3, d: 5});

const diff = second_map.filter((v, k) => first_map.get(k) !== v);

console.log(diff.toString()); // Map { "b": 3, "d": 5 }

<script src="https://cdnjs.cloudflare.com/ajax/libs/immutable/3.8.2/immutable.min.js"></script>

In cases where there might be undefined values in the Map, it's recommended to first check using has, as Map.get(key) will return undefined for non-existent keys. However, using null instead of undefined is preferable for clarity and consistency.

What is the best way to ascertain the variance between two Immutable.js Maps?

Answer №1

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