How to filter and map an array?

Question

I have this object that I need to filter it.

let data = JSON.parse(this.getDataFromArray).map((x: any) => x.isEnabled === true);

I need to get in "data" only ID's of values that "isEnabled" is true.

Hey @ForkExe please try to research a bit more before you ask a new question. Since this is a very simple problem and has been answered too many times before, you could already find solutions by doing a bit more scrolling through the website. Here is one of them that I could find which points the exact issue: stackoverflow.com/questions/31201262/… — em_code
– em_code, Commented Dec 9, 2021 at 14:57

codeandcloud · Accepted Answer · 2021-12-09 16:43:15Z

1

Use Array.prototype.flatMap to achieve the result.

const dataArray = [
  { id: 1, name: "Alice", isEnabled: false },
  { id: 2, name: "Bob", isEnabled: true },
  { id: 3, name: "Charlie", isEnabled: true },
  { id: 4, name: "Dave", isEnabled: true },
  { id: 5, name: "Eve", isEnabled: false },
  { id: 6, name: "Frank", isEnabled: false },
];
let data = dataArray.flatMap(elm => elm.isEnabled ? [elm.id]: []);
console.log(data);

Please note that flatMap cannot be used in IE without a polyfill.

If you need IE support, use Array.prototype.forEach

const dataArray = [
  { id: 1, name: "Alice", isEnabled: false },
  { id: 2, name: "Bob", isEnabled: true },
  { id: 3, name: "Charlie", isEnabled: true },
  { id: 4, name: "Dave", isEnabled: true },
  { id: 5, name: "Eve", isEnabled: false },
  { id: 6, name: "Frank", isEnabled: false },
];
let data = [];
dataArray.forEach((elm) => {
  if (elm.isEnabled) {
    data.push(elm.id);
  }
});
console.log(data);

edited Dec 9, 2021 at 16:43

answered Dec 9, 2021 at 14:47

codeandcloud

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4 Comments

ForkExe Over a year ago

Okey, but I need to store only ID's , not all object

Samathingamajig Over a year ago

@ForkExe Then filter like this, then map the result to just store the ID's

codeandcloud Over a year ago

@ForkExe: Updated the answer to use flatMap

Paul Fitzgerald Over a year ago

nice never saw flatMap

Deepak · Accepted Answer · 2021-12-09 14:59:21Z

0

Try this to filter first, and map to desired property:

JSON.parse(this.getDataFromArray).filter((x: any) => x.isEnabled === true).map((result: any) => result.id);

answered Dec 9, 2021 at 14:59

Deepak

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