Code for my egghead.io course "Understand JavaScript's this Keyword in Depth"

lesson-1-global-context.js

// "use strict";

console.log(this === window);

lesson-2-function-calls-part-1.js

function func() {
    "use strict";
    console.log(this === undefined);
}

func();

lesson-2-function-calls-part-2.js

// "use strict";

function Person(firstName, lastName) {
    this.firstName = firstName;
    this.lastName = lastName;
}

const person = Person("Jane", "Doe");
console.log(person);
console.log(window.firstName);
console.log(window.lastName);

lesson-3-new.js

function Person(firstName, lastName) {
    console.log(this);
    this.firstName = firstName;
    console.log(this);
    this.lastName = lastName;
    console.log(this);
    
    // return this;
}

const person = new Person("Jane", "Doe");

lesson-4-method-calls-part-1.js

const person = {
    firstName: "John",
    sayHi() {
        console.log(`Hi, my name is ${this.firstName}!`);
    }
};

person.sayHi();

lesson-4-method-calls-part-2.js

const person = {
    firstName: "John",
    sayHi() {
        console.log(`Hi, my name is ${this.firstName}!`);
    }
};

const greet = person.sayHi;
greet();

lesson-5-call-apply.js

function sayHi() {
    console.log(`Hi, my name is ${this.firstName}!`);
}

const person = {
    firstName: "Jane",
    lastName: "Doe"
};

sayHi.apply(person);

lesson-6-bind.js

const person = {
    firstName: "John",
    sayHi() {
        console.log(`Hi, my name is ${this.firstName}!`);
    }
};

setTimeout(person.sayHi /* .bind(person) */, 1000);

lesson-7-arrow-functions-part-1.js

const outerThis = this;

const func = () => {
    console.log(this === outerThis);
};

func();
func.call(null);
func.apply(undefined);
func.bind({})();

lesson-7-arrow-functions-part-2.js

const counter = {
    count: 0,
    incrementPeriodically() {
        setInterval(() => {
            console.log(++this.count);
        }, 1000);
    }
};

counter.incrementPeriodically();

lesson-8-classes-part-1.js

class Person {
    constructor(firstName, lastName) {
        this.firstName = firstName;
        this.lastName = lastName;
    }

    sayHi() {
        console.log(`Hi, my name is ${this.firstName}!`);
    }
}

const person = new Person("John", "Doe");
person.sayHi();

lesson-8-classes-part-2.js

class Person {
    sayHi = () => {
        console.log(`Hi, my name is ${this.firstName}!`);
    };

    constructor(firstName, lastName) {
        this.firstName = firstName;
        this.lastName = lastName;
    }
}

const person = new Person("John", "Doe");
const greet = person.sayHi;
greet();