Script for backward-compatibility: https://github.com/douglascrockford/JSON-js/blob/master/json2.js

And call:

var myJsonString = JSON.stringify(yourArray);

Note: The JSON object is now part of most modern web browsers (IE 8 & above). See caniuse for full listing. Credit goes to: @Spudley for his comment below

just reference the object like this:

var array = [{"total_exec_qty":"286595","total_notional":"21820771.72","total_wt_arr_last_slp":"2.4364","total_num_ords":"1630","total_wt_ivwap_slp":"6.0969","total_wt_arr_slp":"1.7889","total_ord_qty":"576991"}];

var object = array[0];

Alternatively you could copy the object and reassign it to the same variable like the following, note: This second method is a bit more expensive.

var data = [{"total_exec_qty":"286595","total_notional":"21820771.72","total_wt_arr_last_slp":"2.4364","total_num_ords":"1630","total_wt_ivwap_slp":"6.0969","total_wt_arr_slp":"1.7889","total_ord_qty":"576991"}];

data = JSON.parse(JSON.stringify(data[0]));

Here is a working example.

You can use array reduce and pass an empty object in the accumulator. Then inside the reduce callback update the accumulator array by adding key and value

let obj = [{
  "Id": 1,
  "Name": "One"
}, {
  "Id": 2,
  "Name": "Two"
}, {
  "Id": 3,
  "Name": "Three"
}]


let newObj = obj.reduce(function(acc, curr) {

  acc[curr.Id] = curr.Name;
  return acc;
}, {})


console.log(newObj)