Replace IDs (strings) in array with references to full objects from another array

Question

I have a source array of "full objects":

[
  {
    "_id": "5b4f9fda7911cf35ef13652d",
    "index": 0,
    "guid": "498f7981-d51f-4904-9441-e182a9f816a1",
    "isActive": true,
    "balance": "$3,621.74",
    "picture": "http://placehold.it/32x32"
  },
  {
    "_id": "5b4f9fdafe3a9a34a23b2384",
    "index": 1,
    "guid": "4d51b6bd-cde1-4537-ab04-00279d31819a",
    "isActive": true,
    "balance": "$2,255.20",
    "picture": "http://placehold.it/32x32"
  },
  {
    "_id": "5b4f9fda630056748bab5ef1",
    "index": 2,
    "guid": "4eafecbf-61d6-430c-83d7-a5cbca464ba2",
    "isActive": true,
    "balance": "$3,831.17",
    "picture": "http://placehold.it/32x32"
  },
  {
    "_id": "5b4f9fdacf21ab443543eaf5",
    "index": 3,
    "guid": "ebbf0837-e651-442f-b2dd-683ca7566e1c",
    "isActive": true,
    "balance": "$2,306.59",
    "picture": "http://placehold.it/32x32"
  },
  {
    "_id": "5b4f9fda29a6076af6fe2653",
    "index": 4,
    "guid": "c3336d60-7adc-424d-b9d9-2a79388296a2",
    "isActive": true,
    "balance": "$2,618.71",
    "picture": "http://placehold.it/32x32"
  },
  {
    "_id": "5b4f9fdad82474982243c996",
    "index": 5,
    "guid": "ad98afcf-b347-4b4c-89ff-60e610eb6429",
    "isActive": true,
    "balance": "$2,785.16",
    "picture": "http://placehold.it/32x32"
  }
]

And I have order array that defines specific order of these items:

[
    "5b4f9e23c98e0e6e6b80a078",
    "5b4f9e232a1e3cb66de39da6",
    "5b4f9e232a4c2cd581820b5e",
    "5b4f9e23cea38324b6dc088b",
    "5b4f9e230fda7c3f47fdcc44",
    "5b4f9e23d8dc8781b55c2d9f",
    "5b4f9e23a2722749bd0cf007",
    "5b4f9e2337826857f21913e2",
    "5b4f9e23a90929808423cc78",
    "5b4f9e23d5f0dc1ea1de2fa9",
    "5b4f9e23c3a98a8d62895f52",
    "5b4f9e2321a33c977199a30f",
    "5b4f9e231217cf22adf41d88",
    "5b4f9e239616ddcd8894fc8f",
    "5b4f9e23a503781b1c281c79",
    "5b4f9e2394bf6e7543f77c80",
    "5b4f9e23a59a30678ecfe6a6",
    "5b4f9e239cbea626e1ef9771",
    "5b4f9e238bca46582cc4245c",
    "5b4f9e2354eba1b141ad4ebe"
]

What I want is to write a method that would:

• replace the ids (string) with reference to the object in source
• so if I delete an item from the "source" - it gets deleted from the "order"
• but if I delete item from "order" - it is NOT deleted from the source

How can I do that?

Answer 1

Turn your source array into a map for easy look up:

const byID = new Map(source.map(el => [el.id, el]));

Then you can easily turn the sorted array into references:

sorted = sorted.map(id => byID.get(id));

To remove an (the fith in this example) element:

sorted.splice(4, 1)

so if I delete an item from the "source" - it gets deleted from the "order"

Thats impossible, you have to manually remove it from the sorted array.