Question

I have two arrays of objects:

var arOne = [
    {key: 'alpha', value: 5},  
    {key: 'beta', value: 11},  
    {key: 'gamma', value: 15},  
    {key: 'delta', value: 12},  
    {key: 'epsilon', value: 55}  
    {key: 'pony', value: 101}
]

var arTwo = [
    {key: 'alpha', value: 5.5},  
    {key: 'beta', value: 11.5},  
    {key: 'gamma', value: 15.5},  
    {key: 'psi', value: 12.5},  
    {key: 'omega', value: 55.5}  
]

I need to merge values into one array of arrays.

Case where the keys match: create an array with the key and append the value from arTwo to arOne.

Case where the keys do not match: if the key exists in arOne, I include the value from arOne and a 0 for arTwo. If the key exists in arTwo, I include a 0 for arOne and the value from arTwo.

Note that arOne and arTwo may be different sizes (see the pony key in arOne).

This is what the result should look like:

var result = [
    ['alpha', 5, 5.5],  
    ['beta', 11, 11.5],  
    ['gamma', 15, 15.5],  
    ['delta', 12, 0],  
    ['epsilon', 55, 0],  
    ['pony', 101, 0],
    ['psi', 0, 12.5],  
    ['omega', 0, 55.5],  
]

I’ve been staring at this all day and scratched all my attempts. Any thoughts?

Answer 1

function combine(obj1, obj2){
    var arr = [], k, i;
    for (k = 0; k < obj1.length; ++k){
        arr.push([obj1[k].key, obj1[k].value]);
    }
    for (k = 0; k < obj2.length; ++k){
        var exists = false;
        for (i = 0; i < arr.length; ++i){
            if(arr[i][0] === obj2[k].key){
               arr[i].push(obj2[k].value);
               var exists = true; 
               break;
            }
        }
        if (!exists){
            arr.push([obj2[k].key, 0, obj2[k].value]);
        }
    }
    for (i = 0; i < arr.length; ++i){
        if (arr[i].length === 2){
            arr[i].push(0);
        }
    }

    return arr;
}

Call like:

var myNewArray = combine(arOne, arTwo);