Facing problem while comparing two javaScript array along with values

Question

var obj1 = { key1: 'value1', key2: 'value2', key3: [] },
    obj2 = { key1: 'value1', key2: 'someOtherValue', key3: [] },
    map = new Map();

Object.keys(obj1).forEach(k => map.set(k, obj1[k]));
Object.keys(obj2).forEach(k => map.get(k) !== obj2[k] && console.log(k + ' is different'));

I taken the piece of code from how to compare two javascript array using angular.foreach but in my scenario need to add array also in map, So please help me out from this. Thanks.

In both object key3 values is same('[]') but in console its getting different. — Bikash Pandit, Jul 15 '20 at 07:41
its not the same, they may both have no elements but they are not the same — Krzysztof Krzeszewski, Jul 15 '20 at 07:42
Does this answer your question? [How to compare arrays in JavaScript?](https://stackoverflow.com/questions/7837456/how-to-compare-arrays-in-javascript) — Krzysztof Krzeszewski, Jul 15 '20 at 07:42
Yeah, but how can i check there is no element difference in both — Bikash Pandit, Jul 15 '20 at 07:44

Nina Scholz · Accepted Answer · 2020-07-15T07:51:54.100

1

You could stringify the value to get a comparable value.

The original code checks the value with primitive types. By using objects, the object reference is used for checking. If you have two different arrays, you have two different object references.

var obj1 = { key1: 'value1', key2: 'value2', key3: [] },
    obj2 = { key1: 'value1', key2: 'someOtherValue', key3: [] },
    map = new Map();

Object.keys(obj1).forEach(k => map.set(k, obj1[k]));
Object.keys(obj2).forEach(k => {
    const value = map.get(k);
    if (value !== obj2[k] && JSON.stringify(value) !== JSON.stringify(obj2[k])) {
        console.log(k + ' is different');
    }
});

edited Jul 15 '20 at 07:51

answered Jul 15 '20 at 07:43

Nina Scholz

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only works if the values of the arrays are supported, ex `undefined`, `function(){}`, `Symbol('')` and `null` will all be transformed into nulls during `JSON.stringify`, sets and maps will also be transformed into objects – Krzysztof Krzeszewski Jul 15 '20 at 07:46

Facing problem while comparing two javaScript array along with values

1 Answers1