Enahnced Object Literals

enhanced-object-literals.js

/* --- No repetition if key: value is identical --- */
// ES5
var es5_getLaptopProperties = function(make, model, year) {
    return {
        make: make,
        model: model,
        year: year
    }
}
es5_getLaptopProperties("Apple", "MacBook", "2015");
// outputs: {make: "Apple", model: "MacBook", year: "2015"}

// ES6
const es6_getLaptopProperties = (make, model, year) => {
    return {
        make,
        model,
        year
    }
}
es6_getLaptopProperties("Apple", "MacBook", "2015");
// outputs: {make: "Apple", model: "MacBook", year: "2015"}


/* --- Shorter methodnames --- */
// ES5
var es5_getLaptopMethods = function (make, model, year) {
    return {
        sayModel: function () {
            return model;
        }
    }
}
es5_getLaptopMethods("Apple", "MacBook", "2015");
// outputs: {sayModel: ƒ}

// ES6
const es6_getLaptopMethods = (make, model, year) => {
    return {
        sayModel() {
            return model;
        }
        // in object methods the ':function()' is now optional
    }
}
es6_getLaptopMethods("Apple", "MacBook", "2015");
// outputs: {sayModel: ƒ}


/* --- Use variables as keys --- */
// ES5
var es5_changeLaptopProperties = function (make, model, year) {
    var key1 = 'make';
    var obj = {
        model: model,
        year: year
    }
    obj[key1] = make;
    return obj;
}
es5_changeLaptopProperties("Apple", "MacBook", "2015");
// outputs: {model: "MacBook", year: "2015", make: "Apple"}


// ES6
const es6_changeLaptopProperties = (make, model, year) => {
    var key1 = 'make';
    var obj = {
        [key1]: make,
        model,
        year
    }
    return obj;
}
es6_changeLaptopProperties("Apple", "MacBook", "2015");


const key = "make";
let i = 0;
const laptop = {
    [key + ++i]: "Apple",
    [key + ++i]: "Dell",
    [key + ++i]: "HP"
}
// also see that dynamic keys are possible
console.log(laptop.make1); //"Apple"
console.log(laptop.make2); //"Dell"
console.log(laptop.make3); //"HP"