Group value in array - Node.js Array

Node.js examples for Array:Array Value

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Description

Group value in array

Demo Code

Array.prototype.groupBy = function (predicate) {
    var results = [];
    var items = this;

    var keys = {}, index = 0;
    for (var i = 0; i < items.length; i++) {
        var selector;
        if (typeof predicate === "string") {
            selector = items[i][predicate];
        } else {/*from  www.j  a  va 2 s.c  om*/
            selector = predicate(items[i]);
        }
        if (keys[selector] === undefined) {
            keys[selector] = index++;
            results.push({ key: selector, value: [items[i]] });
        } else {
            results[keys[selector]].value.push(items[i]);
        }
    }
    return results;
};

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