Filter object array against another object array

Question

I have two arrays simplified like this.

var a = [{
 number: 1,
 name: "A"
}, {
 number: 2,
 name: "B"
}, {
 number: 3,
 name: "C"
}, {
 number: 4,
 name: "D"
}, {
 number: 5,
 name: "E"
}, {
 number: 6,
 name: "F"
}];

var b = [{
 number: 3,
 name: "C"
}, {
 number: 6,
 name: "F"
}];

What I want is to return an array where a is filtered against b. So the result is this.

var result = [{
 number: 1,
 name: "A"
}, {
 number: 2,
 name: "B"
}, {
 number: 4,
 name: "D"
}, {
 number: 5,
 name: "E"
}];

Have looked at alot of other solutions here on stack overflow but can't get it to work.

I am ok with using libaries like underscore.

Answer 1

It is possible to achieve with lodash by the one-line solution.

 var a = [{ number: 1, name: "A" }, { number: 2, name: "B" }, { number: 3, name: "C" }, { number: 4, name: "D" }, { number: 5, name: "E" }, { number: 6, name: "F" }]; var b = [{ number: 3, name: "C" }, { number: 6, name: "F" }]; var result = _.differenceWith(a, b, _.isEqual); console.log(result) 

 <script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.4/lodash.min.js"></script> 

Answer 2

You can use Array#filter . Something like that:

const filterData = (a,b) => {
    return a.filter( (itemA) => {
        return b.some( (itemB) => { 
            return (itemA.number === itemB.number); 
         });
  });
}

I just created a fiddle to test the code: https://jsfiddle.net/mrlew/pb1qqeyd/3/ (you'll have to open console to check results).

Or... in one-line:

const filterData = (a,b) => a.filter( (itemA) => b.some( (itemB) => (itemA.number === itemB.number) ) );

EDIT : thanks to @kzh suggestions, edited to use .some .

Answer 3

var a = [{
 number: 1,
 name: "A"
}, {
 number: 2,
 name: "B"
}, {
 number: 3,
 name: "C"
}, {
 number: 4,
 name: "D"
}, {
 number: 5,
 name: "E"
}, {
 number: 6,
 name: "F"
}];

var b = [{
 number: 3,
 name: "C"
}, {
 number: 6,
 name: "F"
}];

var _ = require('lodash');
var result = _.differenceBy(a,b,'name');

For more informaiton please refer Lodash documentation: https://lodash.com/docs/#differenceBy

Answer 4

You can use the in-built filter function in JavaScript to filter an array with another array check the below code snippet.

 var a = [{ number: 1, name: "A" }, { number: 2, name: "B" }, { number: 3, name: "C" }, { number: 4, name: "D" }, { number: 5, name: "E" }, { number: 6, name: "F" }]; var b = [{ number: 3, name: "C" }, { number: 6, name: "F" }]; var result = a.filter(function(currentValue, index, arr) { var found = false; for (var i = 0; i < b.length; i++) { if (currentValue.number === b[i].number) { found = true; break; } } if (!found) { return currentValue; } }); console.log(result); 

Answer 5

You can do this with plain javascript using filter() , some() and every() .

 var a = [{"number":1,"name":"A"},{"number":2,"name":"B"},{"number":3,"name":"C"},{"number":4,"name":"D"},{"number":5,"name":"E"},{"number":6,"name":"F"}] var b = [{"number":3,"name":"C"},{"number":6,"name":"F"}] var result = a.filter(function(o) { return !b.some(function(e) { return Object.keys(o).length == Object.keys(e).length && Object.keys(o).every(function(k) { return e[k] == o[k] }) }) }) console.log(result) 

Answer 6

var v1 = JSON.parse(a);
var v2 = JSON.parse(b);

var v3 = [] ;


function objectEquals(v1, v2) {

    if (typeof(v1) !== typeof(v2)) {
        return false;
    }
if (v1 instanceof Object && v2 instanceof Object) {

  for (k in v1) {
            r = objectEquals(v1[k], v2[k]);
            if (!r) {
              v3.push(v1[k]);  

            }
        }



}

}

// call the above method passing your two object, and return a new unique array


objectEquals(v1, v2) ;