how to cast in javascript code example

Example 1: javascript type casting int

Number("3.14") // returns 3.14
false.toString()   // returns "false"
String(false)      // returns "false"

Example 2: javascript casting objects

class Person {
  constructor(obj) {
    obj && Object.assign(this, obj);
  }

  getFullName() {
    return `${this.lastName} ${this.firstName}`;
  }
}