@guj/rif-js/src/main/rif.js

Simplify filter,map and such when their use should be conditionnal

// Credits for extension go to :
//     https://gist.github.com/hns/663932/bca04dc7800e66f3b21c08d6ae22260d1d091a60
function Rif() {
}

Rif.prototype = Object.create(Array.prototype);

function turnArrayToRif(arrayToMutate) {
    arrayToMutate.__proto__ = Rif.prototype;
    return arrayToMutate;
}

Rif.of = function (originalArray) {
    let arrayCopy = Array.from(originalArray);
    return turnArrayToRif(arrayCopy);
};

function applyAsRifMethod(funk, thees) {
    return function () {
        thees = thees || this;
        return turnArrayToRif(funk.apply(thees, arguments))
    };
}

function integrateMethodToRif(funkName) {
    let funk = Array.prototype[funkName];
    Rif.prototype[funkName] = applyAsRifMethod(funk);
    Rif.prototype[funkName + "If"] = function (doIMap) {
        if (!doIMap) {
            return () => this;
        }
        return applyAsRifMethod(funk, this);
    };
};

Object.getOwnPropertyNames(Array.prototype)
    .filter(key => key !== `splice`) //<- I'll deal with you the day you'll become a real function you dirty punk, you hybrid monstrosity
    .filter(key => key !== `constructor`)
    .filter(key => Array.prototype[key] instanceof Function)
    .filter(key => {
        const example = [null];
        const result = Array.prototype[key].call(example, x => x);
        if (!(result instanceof Array)) {
            return false;
        }
        return result !== example;
    }).forEach(integrateMethodToRif);

Object.getOwnPropertyNames(Rif)
    .forEach(prop => exports[prop] = Rif[prop]);