Comparing two arrays of objects, and exclude the elements who match values into new array in JS
well, this using lodash or vanilla javascript it depends on the situation.
but for just return the array that contains the duplicates it can be achieved by the following, offcourse it was taken from @1983
var result = result1.filter(function (o1) {
return result2.some(function (o2) {
return o1.id === o2.id; // return the ones with equal id
});
});
// if you want to be more clever...
let result = result1.filter(o1 => result2.some(o2 => o1.id === o2.id));
Just using the Array iteration methods built into JS is fine for this:
var result1 = [
{id:1, name:'Sandra', type:'user', username:'sandra'},
{id:2, name:'John', type:'admin', username:'johnny2'},
{id:3, name:'Peter', type:'user', username:'pete'},
{id:4, name:'Bobby', type:'user', username:'be_bob'}
];
var result2 = [
{id:2, name:'John', email:'[email protected]'},
{id:4, name:'Bobby', email:'[email protected]'}
];
var props = ['id', 'name'];
var result = result1.filter(function(o1){
// filter out (!) items in result2
return !result2.some(function(o2){
return o1.id === o2.id; // assumes unique id
});
}).map(function(o){
// use reduce to make objects with only the required properties
// and map to apply this to the filtered array as a whole
return props.reduce(function(newo, name){
newo[name] = o[name];
return newo;
}, {});
});
document.body.innerHTML = '<pre>' + JSON.stringify(result, null, 4) +
'</pre>';If you are doing this a lot, then by all means look at external libraries to help you out, but it's worth learning the basics first, and the basics will serve you well here.
The same result can be achieved using Lodash.
var result1 = [
{id:1, name:'Sandra', type:'user', username:'sandra'},
{id:2, name:'John', type:'admin', username:'johnny2'},
{id:3, name:'Peter', type:'user', username:'pete'},
{id:4, name:'Bobby', type:'user', username:'be_bob'}
];
var result2 = [
{id:2, name:'John', email:'[email protected]'},
{id:4, name:'Bobby', email:'[email protected]'}
];
var result3 = _(result1)
.differenceBy(result2, 'id', 'name')
.map(_.partial(_.pick, _, 'id', 'name'))
.value();
console.log(result3);<script src="https://cdn.jsdelivr.net/lodash/4.16.4/lodash.min.js"></script>You can get the desired result applying a difference between both arrays using the properties "id" and "name" as a way to "link" elements between them. If any of those properties are different, the elements are considered different (improbably in your case because id seems to be unique).
Lastly, you have to map the result in order to "omit" the undesired properties of the object.
Hope it helps.