push into array of nested objects

Question

My array is of multiple objects

[
  { key: 'javascript', count: 12 },
  { key: 'typescript', count: 15 },
  { key: 'angular', count: 13 }
]

How can I push inside each object to make it like

[
  { key: 'javascript', count: 12, selected: false },
  { key: 'typescript', count: 15, selected: false },
  { key: 'angular', count: 13, selected: false }
]

Answer 1

let t = [
  { key: 'javascript', count: 12 },
  { key: 'typescript', count: 15 },
  { key: 'angular', count: 13 }
];

t.forEach(myObj => (myObj.selected = false));

console.log(t);

After author commented:

let t = {
0:[ { key: 'javascript', count: 12 }, { key: 'typescript', count: 15 }, { key: 'angular', count: 13 } ], 
99:[ { key: 'javascript', count: 12 }, { key: 'typescript', count: 15 }, { key: 'angular', count: 13 } ], 
};

Object.keys(t).forEach(myNum => 
t[myNum].forEach(myObj => myObj.selected = false));

console.log(t);

Answer 2

You could use Array#Map

var items = [
{key:"javascript" , count : 12},
{key:"typescript", count: 15},
{key:"angular" , count: 13}
]

console.log(items.map(item=>({...item, selected: false})))

Answer 3

const data = [
  [
    { key: 'javascript', count: 12 },
    { key: 'typescript', count: 15 },
    { key: 'angular', count: 13 }
  ]
];

data[0].forEach(item => (item.selected = false));

console.log(data);