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JavaScript: Sort an array of JavaScript objects

JavaScript Object: Exercise-10 with Solution

Write a JavaScript program to sort an array of JavaScript objects.

Sample Object:

var library = [ 
   {
       title:  'The Road Ahead',
       author: 'Bill Gates',
       libraryID: 1254
   },
   {
       title: 'Walter Isaacson',
       author: 'Steve Jobs',
       libraryID: 4264
   },
   {
       title: 'Mockingjay: The Final Book of The Hunger Games',
       author: 'Suzanne Collins',
       libraryID: 3245
   }];

Expected Output:

[[object Object] {
  author: "Walter Isaacson",
  libraryID: 4264,
  title: "Steve Jobs"
}, [object Object] {
  author: "Suzanne Collins",
  libraryID: 3245,
  title: "Mockingjay: The Final Book of The Hunger Games"
}, [object Object] {
  author: "The Road Ahead",
  libraryID: 1254,
  title: "Bill Gates"
}]

Sample Solution: -

HTML Code:

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <title>JavaScript program to sort an array of JS objects</title>
</head>
<body>

</body>
</html>

JavaScript Code:

var library = [ 
   {
       title: 'Bill Gates',
       author: 'The Road Ahead',
       libraryID: 1254
   },
   {
       title: 'Steve Jobs',
       author: 'Walter Isaacson',
       libraryID: 4264
   },
   {
       title: 'Mockingjay: The Final Book of The Hunger Games',
       author: 'Suzanne Collins',
       libraryID: 3245
   }];

var sort_by = function(field_name, reverse, initial){

   var key = initial ?
       function(x)
             {
               return initial(x[field_name]);
             } :
       function(x) 
             {
               return x[field_name];
             };

   reverse = !reverse ? 1 : -1;

   return function (x, y) {
       return x = key(x), y = key(y), reverse * ((x > y) - (y > x));
     } ;
};


var newobj = library.sort(sort_by('libraryID', true, parseInt));

console.log(newobj);

Sample Output:

[{"title":"Steve Jobs","author":"Walter Isaacson","libraryID":4264},{"title":"Mockingjay: The Final Book of The Hunger Games","author":"Suzanne Collins","libraryID":3245},{"title":"Bill Gates","author":"The Road Ahead","libraryID":1254}]

Flowchart:

Flowchart: JavaScript - Sort an array of JavaScript objects.

Live Demo:

See the Pen javascript-object-exercise-10 by w3resource (@w3resource) on CodePen.


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Previous: Write a JavaScript program to calculate the area and perimeter of a circle. Create two methods to calculate the area and perimeter. The radius of the circle will be supplied by the user.
Next: Write a JavaScript function to print all the methods in an JavaScript object.

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JavaScript: Tips of the Day

instance

class Calc {
	constructor() {
		this.count = 0 
	}

	increase() {
		this.count ++
	}
}

const calc = new Calc()
new Calc().increase()

console.log(calc.count)

We set the variable calc equal to a new instance of the Calc class. Then, we instantiate a new instance of Calc, and invoke the increase method on this instance. Since the count property is within the constructor of the Calc class, the count property is not shared on the prototype of Calc. This means that the value of count has not been updated for the instance calc points to, count is still 0.

Ref: https://bit.ly/2Hcpkm6