Merge property from an array of objects into another based on property value lodash

Question

I have 2 arrays of objects, they each have an id in common. I need a property from objects of array 2 added to objects array 1, if they have matching id<

Answer 1

A solution in plain Javascript

This is a more generic solution for merging two arrays which have different properties to union in one object with a common key and some properties to add.

var array1 = [{ id: 1, name: 'tom', age: 24 }, { id: 2, name: 'tim', age: 25 }, { id: 3, name: 'jack', age: 24 }, ],
    array2 = [{ id: 1, gender: 'male', eyeColour: 'blue', weight: 150 }, { id: 2, gender: 'male', eyeColour: 'green', weight: 175 }, { id: 3, gender: 'male', eyeColour: 'hazel', weight: 200 }, ];

function merge(a, b, id, keys) {
    var array = [], object = {};

    function m(c) {
        if (!object[c[id]]) {
            object[c[id]] = {};
            object[c[id]][id] = c[id];
            array.push(object[c[id]]);
        }
        keys.forEach(function (k) {
            if (k in c) {
                object[c[id]][k] = c[k];
            }
        });
    }
    a.forEach(m);
    b.forEach(m);
    return array;
}

document.write('
' + JSON.stringify(merge(array1, array2, 'id', ['name', 'age', 'eyeColour']), 0, 4) + '
');