Event listener

element.addEventListener(type, listener);

Example:

btn.addEventListener("click", func1);

Higher-order function example

Function 1:

function add(num1, num2) {
  return num1 + num2;
}

Function 2:

function sub(num1, num2) {
  return num1 - num2;
}

Higher-order function:

function calculator(num1, num2, operator) {
  return operator(num1, num2);
}

Debugging JavaScript

debugger;
calculator(3, 4, sub);

• Use in the browser console to pause execution and inspect values

Switch statement

switch (expression) {
  case expression:
    break;
  default:
    break;
}

Objects in JavaScript

const housekeeper = {
  name: "Angel",
  age: 19,
  hasWorkPermit: true,
  languages: ["French", "English"],
};

Accessing properties:

console.log(housekeeper.age);