JavaScript Intermediate Cheat Sheet

{{lang-javascript}}function externalFunction(x) {
  return function internalFunction(y) {
    return x + y;
  };
}

const add5 = externalFunction(5);
console.log(add5(3)); // Output: 8

{{lang-javascript}}class Animal {
  constructor(name) {
    this.name = name;
  }

  talk() {
    console.log("generic sound");
  }
}

class Dog extends Animal {
  constructor(name) {
    super(name);
  }

  talk() {
    console.log("Bau!");
  }
}

const jsonString = '{"name":"Bob","age":25,"city":"New York","interests":["music","sport"]}';

const  jsonObj = JSON.parse(jsonString);
console.log(jsonObj );
// Output: { name: 'Bob', age: 25, city: 'New York', interests: [ 'music', 'sport' ] }

console.log(jsonObj.name); // Output: Bob
console.log(jsonObj.interests[0]); // Output: music
console.log(typeof jsonObj); // Output: object

let firstName = "John";
let lastName = "Doe";

let text = \`Welcome ${firstName}, ${lastName}!\`; 
//Output: Welcome John, Doe!

{{lang-javascript}}function Person(name) {
  this.name = name;
}

Person.prototype.greet = function() {
  console.log(`Hello, I'm ${this.name}`);
};

const person1 = new Person("Alice");
person1.greet(); // Output: Hello, I'm Alice

{{lang-javascript}}fetch('https://api.example.com/data')
  .then(response => response.json())
  .then(data => console.log(data))
  .catch(error => console.error(error));

const myObj= {
  name: "Alice",
  age: 30,
  city: "Rome",
  interests: ["programming", "travel"]
};

const JSONstring = JSON.stringify(myObj);
console.log(JSONstring );
// Output: {"name":"Alice","age":30,"city":"Rome","interests":["programming","travel"]}

console.log(typeof JSONstring); // Output: string