Binding this context

ex-1.js

const Person = {
    firstName: "Lawrence",
    lastName: "Eagles",
    sayName: function () {
        setTimeout(function() {
            console.log("my fullname is " + this.firstName + " " + this.lastName)
        }.bind(this), 100) // binds this here.
    }
}
console.log(Person.sayName()) // returns "my fullname is Lawrence Eagles"

ex-2.js

const developer = {
    firstName: "John",
    lastName: "Doe",
    getDevName: function() {
        let fullName = this.firstName + " " + this.lastName;
        return fullName;
    }
}

const logDevName = function () {
    console.log('logged: ' + this.getDevName());
}

// binds the `this`in the boostedLogDevName function to the developer object.
const boostedLogDevName = logDevName.bind(developer) 

boostedLogDevName(); // "developer's name is:John Doe"