Creating an associative array in JavaScript with push()?

For this, use forEach() loop along with push(). Following is the code −

Example

var studentDetails=
[
   {
      studentId:1,
      studentName:"John"
   },
   {
      studentId:1,
      studentName:"David"
   },
   {
      studentId:2,
      studentName:"Bob"
   },
   {
      studentId:2,
      studentName:"Carol"
   }
]
studentObject={};
studentDetails.forEach (function (obj){
   studentObject[obj.studentId] = studentObject[obj.studentId] || [];
   studentObject[obj.studentId].push(obj.studentName);
});
console.log(studentObject);

To run the above program, you need to use the following command −

node fileName.js.

Here, my file name is demo116.js.

Output

This will produce the following output −

PS C:\Users\Amit\JavaScript-code> node demo116.js
{ '1': [ 'John', 'David' ], '2': [ 'Bob', 'Carol' ] }

AmitDiwan

Published on 09-Sep-2020 13:18:40

• Related Questions & Answers
• Creating an associative array in JavaScript?
• Dynamically creating keys in JavaScript associative array
• JavaScript in filter an associative array with another array
• Sorting an associative array in ascending order - JavaScript
• Updating an array with $push in MongoDB
• Prefix sums (Creating an array with increasing sum) with Recursion in JavaScript
• Looping numbers with object values and push output to an array - JavaScript?
• Length of a JavaScript associative array?
• JavaScript creating an array from JSON data?
• PHP array_push() to create an associative array?
• PHP Pushing values into an associative array?
• PHP Associative Array
• Creating a JavaScript array with new keyword.
• Convert an object to associative array in PHP
• How to push an array in MongoDB?