Group array

Group array

by Boban Stojanovski

JavaScript

var origArr = [
    {food: 'apple', type: 'fruit'},
    {food: 'potato', type: 'vegetable'},
        {food: 'potato2', type: 'vegetable'},
        {food: 'potato3', type: 'vegetable'},
    {food: 'banana', type: 'fruit'}
];

/*[
    {type: 'fruit', foods: ['apple', 'banana']},
    {type: 'vegetable', foods: ['potato']}
]*/

function transformArr(orig) {
    var newArr = [],
        types = {},
        newItem, i, j, cur;
    for (i = 0, j = orig.length; i < j; i++) {
        cur = orig[i];
        if (!(cur.type in types)) {
            types[cur.type] = {type: cur.type, foods: []};
            newArr.push(types[cur.type]);
        }
        types[cur.type].foods.push(cur.food);
    }
    return newArr;
}

console.log(transformArr(origArr));