javascript this manipulation example

thisManipulation.js

function greet() {
    return "Hello " + this.name ;
}

const john = {
    name: "John"
}

const jane = {
    name: "Jane"
}

greet.apply(jhon);
// <- "Hello Jhon"

jane.greet = greet;
jane.greet();
// <- "Hello Jane"

greet();
// <- "Hello "