how to append data to an object javascript code example

Example 1: object javascript append

var list = [];

list.push({name:'John', last_name:'Doe'});
list.push({name:'Jane', last_name:'Doe'});

console.log(list);
/* Result:
[
  {
    "name": "John",
    "last_name": "Doe"
  },
  {
    "name": "Jane",
    "last_name": "Doe"
  }
]
*/

Example 2: javascript append to object

How about storing the alerts as records in an array instead of properties of a single object ?

var alerts = [ 
    {num : 1, app:'helloworld',message:'message'},
    {num : 2, app:'helloagain',message:'another message'} 
]
And then to add one, just use push:

alerts.push({num : 3, app:'helloagain_again',message:'yet another message'});