code from lecture Frontend Development (2020-11-05)

calculator_closure.js

function calculator() {
    let value = 0

    return function (difference) {
        value += difference
        console.log(value)
    }
}

const calulator1 = calculator()
calulator1(10) // 10
calulator1(-1) // 9

code_from_lecture.js

function newCounter(name) {
    for(let i = 0; i < 10; i++) {

    }
    
    let i = 0;
    return function () {
        i++;
        console.log(name + '; ' + i); 
    }
}

const counter1 = newCounter('test')
counter1() // test; 1 
counter1() // test; 2 

class Counter {
    constructor(name) {
        this.name = name
        this.i = 0
    }
    increment() {
        this.i++;
        console.log(name + '; ' + this.i);        
    }
}
const counter2 = new Counter('test')
counter2.increment() // test; 1 

module.js

(function () {
    var someVariable = 'irrelevant'
    console.log(someVariable); 
}());

function main () {
    var someVariable = 'irrelevant'
    console.log(someVariable); 
}

main()