How to get the difference between two arrays of objects in JavaScript

Question

I have two result sets like this:

// Result 1
[
    { value: \"0\", display: \"Jamsheer\" },
    { value: \"1\", display: \"Muhammed\" },
    { value: \"2\",         


        

Answer 1

I prefer map object when it comes to big arrays.

// create tow arrays
array1 = Array.from({length: 400},() => ({value:Math.floor(Math.random() * 4000)}))
array2 = Array.from({length: 400},() => ({value:Math.floor(Math.random() * 4000)}))

// calc diff with some function
console.time('diff with some');
results = array2.filter(({ value: id1 }) => array1.some(({ value: id2 }) => id2 === id1));
console.log('diff results ',results.length)
console.timeEnd('diff with some');

// calc diff with map object
console.time('diff with map');
array1Map = {};
for(const item1 of array1){
    array1Map[item1.value] = true;
}
results = array2.filter(({ value: id2 }) => array1Map[id2]);
console.log('map results ',results.length)
console.timeEnd('diff with map');