convert array of objects to object js code example

Example 1: how to convert an array into an object using javascript

// This function counts instances of elements in an array
// the return object has the array elements as keys
// and number of occurrences as it's value
const arrToInstanceCountObj = arr => arr.reduce((obj, e) => {
  obj[e] = (obj[e] || 0) + 1;
  return obj;
}, {});

arrToInstanceCountObj(['h', 'e', 'l', 'l', 'o', 'w', 'o', 'r', 'l', 'd'])
/*
  {
    h: 1,
    e: 1,
    l: 3,
    o: 2,
    w: 1,
    r: 1,
    d: 1,
  }
*/

Example 2: javascript convert array to object

function arrayToObject(arr) {
    var obj = {};
    for (var i = 0; i < arr.length; ++i){
        obj[i] = arr[i];
    }
    return obj;
}
var colors=["red","blue","green"];
var colorsObj=arrayToObject(colors);//{0: "red", 1: "blue", 2: "green"}