Getting only requested item from every object Javascript

Question

I am trying to figure out if I can send only relevant javascript info to the frontend from the backend because I want to hide things like ID, and others when my frontend makes a request.

To put things in perspective, here is a dummy code.

[
 {
  "_id": "215874514845452155",
  "greeting":"Hello there"
 },
 {
  "_id": "181474545841541515",
  "greeting": "General Kenobi"
 },
]

when requesting, I want to get result like:

[
 {
  "greeting": "Hello there"
 },
 {
  "greeting": "General Kenobi"
 },
]

I am still learning stuff and I know about loop function but I want to know if there is some neat trick to it. I am coming from R programming, we hate loops.

I think this is what you want: https://stackoverflow.com/questions/9598505/mongoose-retrieving-data-without-id-field — Anmol, Feb 05 '21 at 10:18
Just for extra information, if I wanted more than one item. How would I do with map function? — ashish bajaj, Feb 05 '21 at 10:21
Please check the duplicates: Use either https://stackoverflow.com/a/53718921/3082296 OR https://stackoverflow.com/a/46839399/3082296 — adiga, Feb 05 '21 at 10:22

Jamiec · Accepted Answer · 2021-02-05T10:31:51.870

0

Use Array.prototype.map:

const input = [
 {
  "_id": "215874514845452155",
  "greeting":"Hello there",
  "other":"foo"
 },
 {
  "_id": "181474545841541515",
  "greeting": "General Kenobi",
  "other":"bar"
 },
];

const result = input.map(({greeting,other}) => ({greeting,other}));
console.log(result);

The above is a shorthand way of writing this:

const input = [
 {
  "_id": "215874514845452155",
  "greeting":"Hello there",
  "other":"foo"
 },
 {
  "_id": "181474545841541515",
  "greeting": "General Kenobi",
  "other":"bar"
 },
];

const result = input.map(x => {
  return {
    greeting: x.greeting,
    other: x.other
  }
});
console.log(result);

edited Feb 05 '21 at 10:31

answered Feb 05 '21 at 10:17

Jamiec

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@ashishbajaj it might be hard to understand what thats doing if you're not used to destructuring/object creation. check the update – Jamiec Feb 05 '21 at 10:32
Yes, I get it. The new update also works but I think I will go with destructuring. Looks neat. – ashish bajaj Feb 05 '21 at 10:37
@ashishbajaj the second one has a lot of repetition, which is why the destructing route is nicer – Jamiec Feb 05 '21 at 10:38

Getting only requested item from every object Javascript

1 Answers1