convert array of objects to object keys with array javascript code example

Example 1: javascript array to object with keys

let arr = [{a: 'a', b: 1, c: 'c'}, {a: 'a', b: 2, c: 'c'}, {a: 'a', b: 3, c: 'c'}]:
 let mapped = arr.reduce (function (map, obj) { 
        map[obj.b] = obj; 
        return map;
      },{}); // reduce
console.log (mapped); // {1: {a: 'a', b: 1, c: 'c'}, 2: {a: 'a', b: 2, c: 'c'}, 3: {a: 'a', b: 3, c: 'c'}

Example 2: es6 array to object keys

const subLocationTypes = (location.subLocationTypes || []).reduce((add, cur) => {
add[cur.key] = cur.value;
return add;
}, {});