array prototype javascript code example

Example 1: js get array item by property

const jsObjects = [
  {id: 1, displayName: "First"}, 
  {id: 2, displayName: "Second"}, 
  {id: 3, displayName: "Third"}, 
  {id: 4, displayName: "Fourth"}
]

// You can use the arrow function expression:
var result = jsObjects.find(obj => {
	// Returns the object where
	// the given property has some value 
  	return obj.id === 1
})

console.log(result)

// Output: {id: 1, displayName: "First"}

Example 2: array prototype js

Array.prototype.myUcase = function() {
  for (i = 0; i < this.length; i++) {
    this[i] = this[i].toUpperCase();
  }
};
var fruits = ["Banana", "Orange", "Apple", "Mango"];
fruits.myUcase();
console.log(fruits)

Example 3: function prototype javascript

function Person(name) {
  this.name = name;
}
Person.prototype.getName = function() {
  return this.name;
}

var person = new Person("John Doe");
person.getName() //"John Doe"