customFilter.txt

/*
* A simple function that returns the objects between a range of given values, and grouped by a given key
*/

Array.prototype.customFilter = function(group, range, low, high) {
    if (!(array instanceof Array)) {
        throw new Error("Invalid array");
    }

    var result = {};

    this.forEach(function(item) {
        if (result && group && item[group] && !result[item[group]]) {
            result[item[group]] = [];
        }

        if (item && range && group && item[range] && item[group] && result[item[group]]) {
            if (item[range] >= low && item[range] <= high) {
                result[item[group]].push(item);
            }
        }
    });

    return result;
}

var array = [{name: 'Ankush', age: 26, gender: 'M'}, {name: 'Sakshi', age: 36, gender: 'F'}, {name: 'Mayank', age: 38, gender: 'M'}, {name: 'Akshay', age: 35, gender: 'M'}, {name: 'Anita', age: 36, gender: 'F'}, {name: 'Rakesh', age: 52, gender: 'M'}];

array.customFilter('gender', 'age', 30, 40);