prototype.js

// new problem correct this
// function std(name,gender){
//   this.name = name;
//   this.gender = gender;
// }

// std.prototype.getBio = ()=>{
//   console.log(this, this.name,'sfasd');
// }

// let std1 = new std("Himani","Female");

// std1.getBio()

// solution
// function std(name,gender){
//   this.name = name;
//   this.gender = gender;
// }

// std.prototype.getBio = function() {
//   console.log(this, this.name,'sfasd');
// }

// let std1 = new std("Himani","Female");

// std1.getBio()

// other e.g

class People {
    name;
    constructor(name) {
      this.name = name;
    }
    getName() {
      return this.name;
    }
    setName(name) {
      this.name = name;
    }
  }
  
  let person = new People('Jon Snow');
  console.log(person.getName()); // Jon Snow
  
  person.setName('Dany');
  console.log(person.getName()); //Dany
  console.log(person); // People {name: "Dany"} __proto__: People
  
  // example
  let newVariable = function () {
    this.a = 1;
    this.b = 2;
  };
  let newObject = new newVariable(); // {a: 1, b: 2}
  // add properties in newVariable  function's prototype
  newVariable.prototype.b = 3;
  newVariable.prototype.c = 4;
  // Now we can see that the properties that we assign to newVariable we can also use this with newObject variable.
  console.log(newObject.a); // 1
  console.log(newObject.b); // 2
  console.log(newObject.c); // 4
  console.log(newObject.d); // undefined
  
  //   example
  // Adding Shared properties to Constructor’s .prototype Property and Define a constructor for Circle objects.
  
  function Circle4(radius) {
    this.radius = radius || 1.0;
    this.getArea = function () {
      return this.radius * this.radius * Math.PI;
    };
  }
  
  var circle1 = new Circle4();
  Circle4.prototype.getCircumference = function () {
    return 2 * this.radius * Math.PI;
  };
  Circle4.prototype.color = 'green';
  //   The new properties are available to all instances, including existing ones
  
  console.log(circle1.getCircumference());
  console.log(circle1.color, circle1);
  
  var circle2 = new Circle4(1.5);
  console.log(circle2.getArea());
  console.log(circle2.getCircumference());
  console.log(circle2.color);
  
  //    example
  var doSomething = function () {};
  console.log(doSomething.prototype); // {} __proto__: Object
  
  function doSomethingNew() {}
  doSomethingNew.prototype.foo = 'bar'; // add a property onto the prototype
  var doSomeInstancing = new doSomethingNew();
  doSomeInstancing.prop = 'some value'; // add a property onto the object
  console.log(doSomeInstancing); // prop: "some value"
  
  // example
  specified('hello world'); // => 'h e l l o  w o r l d'
  function specified(str) {
    return str.split('').join(' ');
  }
  // place the specified function directly on the String object
  String.prototype.specified = function () {
    return this.split('').join(' ');
  };
  console.log('hello world'.specified());
  
  // example
  
  function Person() {}
  Person.prototype.greeting = function () {
    alert("Hi! I'm " + this.name.first + '.');
  };
  
  // console.log(Person.prototype, Person.greeting());
  
  function Teacher() {}
  Teacher.prototype = Object.create(Person.prototype);
  
  Object.defineProperty(Teacher.prototype, 'constructor', {
    value: Teacher,
    enumerable: false, // so that it does not appear in 'for in' loop
    writable: true,
  });
  
  console.log(Teacher.prototype);
  Teacher.prototype.greeting = function () {
    let prefix;
  
    if (
      this.gender === 'male' ||
      this.gender === 'Male' ||
      this.gender === 'm' ||
      this.gender === 'M'
    ) {
      prefix = 'Mr.';
    } else if (
      this.gender === 'female' ||
      this.gender === 'Female' ||
      this.gender === 'f' ||
      this.gender === 'F'
    ) {
      prefix = 'Ms.';
    } else {
      prefix = 'Mx.';
    }
  
    console.log(
      'Hello. My name is ' +
        prefix +
        ' ' +
        this.name.last +
        ', and I teach ' +
        this.subject +
        '.'
    );
  };
  
  let teacher1 = new Teacher(
    'Dave',
    'Griffiths',
    31,
    'male',
    ['football', 'cookery'],
    'mathematics'
  );
  // console.log(teacher1.greeting(), 'teacher1')
  
  // __proto__: doSomethingNew
  
  // custom filter
  Array.prototype.mfilter = function (fun) {
    var filtered = [];
    console.log(this); //output: [1,2,3,4,5,6]
    console.log(fun);
    // output:
    //  function (element, index, arr) {
    //    return element > 5;
    //  }
  
    for (let i = 0; i < this.length; i++) {
      if (fun(this[i], i, this)) filtered.push(this[i]);
    }
    return filtered;
  };
  
  var returnedArr = [1, 2, 3, 4, 5, 6].mfilter(function (element, index, arr) {
    return element > 5;
  });
  
  console.log(returnedArr, 'returnedArr');
  
  function object1() {}
function object2() {}
object1.prototype = Object.create(object2.prototype);
const object3 = new object1();
console.log(object1.prototype.isPrototypeOf(object3));
// expected output: true
console.log(object2.prototype.isPrototypeOf(object3));
// expected output: true