inline-reorder.js

//we have an array of objects A and an array of indexes B.  Reorder objects
//in array A with given indexes in array B. Do not change array A's length;

var A = ['C', 'D', 'E', 'F', 'G'];
var B = [3, 0, 4, 1, 2];


function resort(arr, order) {
    let idx=0;
    for(var start=0;start<arr.length;start++) {
        for(var i=start;i<arr.length;i++) {
           if(B[i] == idx) {
               let value = arr.splice(i, 1);
               arr.splice(idx, 0, value[0]);

               value = order.splice(i, 1);
               order.splice(idx, 0, value[0]);
               idx++;
               break;
           }
        }
    }
}

resort(A, B);

console.log(A); // [D, F, G, C, E]
console.log(B); // [0, 1, 2, 3, 4]

actually, this is a much better way to do it....

let A = ['C','D','E','F','G'];
let B = [  3,  0,  4,  1,  2];

sort(A, B);

console.log(A); //D, F, G, C, E

function sort(values, sequence) {
  let indexed = [];
  
  sequence.forEach((value, idx) => indexed[value] = values[idx]);
  indexed.forEach((value, idx) => values[idx] = value);
}