Link arrays in an object of arrays to sort by one of the arrays

user_12816081 0
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I have an object with the following structure:

let obj = {
    "foo": ["orange", "apple", "pear", "grape", "lime"],
    "bar": [12, 6, 18, 3, 22],
    "bat": ["a", "b", "c", "d", "e"]
};

I want to sort by bar but also retain the order of foo and bat relative to bar, like so:

obj = {
    "foo": ["grape", "apple", "orange", "pear", "lime"],
    "bar": [3, 6, 12, 18, 22],
    "bat": ["d", "b", "a", "c", "e"]
};

Is there a tidy way to do this, or do I need to convert it to an array of arrays, sort by index (e.g., arr.sort((a,b) => a[1] - b[1]);), and convert back to the object?

object sorting arrays javascript
2 Answers

const obj = {
  "foo": ["orange", "apple", "pear", "grape", "lime"],
  "bar": [12, 6, 18, 3, 22],
  "bat": ["a", "b", "c", "d", "e"]
};

// get original indices of sorted bar
const indices = obj.bar
  .map((value, index) => ({ value, index }))
  .sort(({ value: a }, { value: b }) => a - b)
  .map(({ index }) => index);

// iterate over obj's values to reorder according to indices
const res = 
  Object.entries(obj)
  .reduce((acc, [key, value]) => ({ ...acc, [key]: indices.map(i => value[i]) }), {});

console.log(res);

user_74863130

You can create a temp array base on all values. Then you can sort that array based on bar. Once sorted, Just fill data to new response while iterating.

const obj = {
  foo: ["orange", "apple", "pear", "grape", "lime"],
  bar: [12, 6, 18, 3, 22],
  bat: ["a", "b", "c", "d", "e"],
};

const arr = obj.bar
  .map((bar, index) => ({
    bar,
    index,
  }))
  .sort((x, y) => x.bar - y.bar);
  
console.log(arr);

const res = arr.reduce(
  (map, { bar, index }, i) => {
    map.bar[i] = bar;
    map.foo[i] = obj.foo[index];
    map.bat[i] = obj.bat[index];
    return map;
  },
  { foo: [], bar: [], bat: [] }
);

console.log(res);

user_15943590
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