krazov

function letsWasteParam(array, getOriginal) {
    for (var i = 0; i < array.length; i++) {
        array[i] = array[i] * 2;
    }
    
    if (!getOriginal) {
        return 'Doubled array: ' + array;
    } else {
        return 'Original array: ' + array; // oops
    }

krazov

// ES5
function safeGuardES5(x) {
    x = x || 7;
    
    // magic
}

function safeGuardES5immutable(paramX) {
    var x = paramX || 7;
    

krazov

function doingSomething3D(params) {
    var x = params.x || 0;
    var y = params.y || 0;
    var z = params.z || 0;
    
    return 'x: ' + x +', y: ' + y + ', z: ' + z;
}

function theNewBlack({ x = 0, y = 0 , z = 0 } = {}) {
    return `x: ${x}, y: ${y}, z: ${z}`;

krazov

function ArrayContainer(array) {
    this.array = array;
}

// before
ArrayContainer.prototype.getNewOrder = function (startAt) {
    if (!startAt) {
        return this.array;
    }
    

krazov

const object1 = {
    name:    'John',
    surname: 'Carbonlover'
};

const object2 = Object.assign(object1, {
    name: 'Frank'
});

// object1.name is now 'Frank', the same like object2’s

krazov

const cantTouchThis = {
    id:   1,
    type: 'fromage', 
    items: {
        knife: 'bowie',
        fork:  'krautrock'
    }
};

Object.freeze(cantTouchThis);

krazov

function fibonacciProcessed(x) {
    return new Promise(resolve => {
        const calculation = function (resolveFn, n = 0, a = 0, b = 1) {
            if (n > 1) {
                setImmediate(() => {
                    calculation(resolveFn, n - 1, b, a + b);
                });
            }

            // else

krazov

// piece taken from: https://medium.com/javascript-scene/reduce-composing-software-fe22f0c39a1d#.4chgx5fc0
const map = (fn, arr) => arr.reduce((acc, item, index, arr) => {
    return acc.concat(fn(item, index, arr));
}, []);

krazov

// piece taken from: https://medium.com/javascript-scene/reduce-composing-software-fe22f0c39a1d#.4chgx5fc0
const filter = (fn, arr) => arr.reduce((newArr, item) => {
    return fn(item) ? newArr.concat([item]) : newArr;
}, []);

krazov

const slice = (array, from, to) => {
    const startIndex = from < 0 ? array.length + from : from;
    const endIndex = to ? (to < 0 ? index < array.length + to : index < to) : index < array.length;
    
    return array.reduce((accumulated, current, index) => {    
        return index >= startIndex && index < endIndex ? accumulated.concat(current) : accumulated;
    }, []);
};