查找数组对象数组的索引

Question

I need to find the index of an array of array object where it is true. My array:

[
 [
  {id: 1, status: false}, 
  {id: 2, status: true}
 ],
 [
  {id: 13, status: false}, 
  {id: 14, status: false}
 ],
 [
  {id: 18, status: true}, 
  {id: 19, status: false}
 ]
]

In the case above I should expect index 0 and 2 to be returned.

Answer 1

Use reduce to get indices of the elements where some items fulfill the condition:

input.reduce((acc, arr, i) => (
    arr.some(obj => obj.status) && acc.push(i)
, acc), [])

 const input = [[{"id":1,"status":false},{"id":2,"status":true}],[{"id":13,"status":false},{"id":14,"status":false}],[{"id":18,"status":true},{"id":19,"status":false}]]; const result = input.reduce((acc, arr, i) => ( arr.some(obj => obj.status) && acc.push(i) , acc), []); console.log(result);

Answer 2

There are two steps in the solution of the problem.

• First traverse the array
• Second check the condition. You can check the condition using two array methods.
  • some: Checks if any of the elements in an array pass a test and returns true or false based on the test.
  • filter: Creates an array based on condition and that's the reason I checked array length in the following code.

 const data = [ [ { id: 1, status: false }, { id: 2, status: true }, ], [ { id: 13, status: false }, { id: 14, status: false }, ], [ { id: 18, status: true }, { id: 19, status: false }, ], ]; let ret = []; data.forEach((x, i) => { if (x.some((y) => y.status)) ret.push(i); }); console.log(ret); ret = []; data.forEach((x, i) => { if (x.filter((y) => y.status).length > 0) ret.push(i); }); console.log(ret);

I have used both some and filter methods to check the condition and for array traversese I have used array forEach method.

Answer 3

Basically same solution as from marzelin, but more readable in my opinion. The comma operator in the callback return value can be quite confusing.

 const data = [ [ {id: 1, status: false}, {id: 2, status: true} ], [ {id: 13, status: false}, {id: 14, status: false} ], [ {id: 18, status: true}, {id: 19, status: false} ] ] //pV=previous value, cV=current value, cI=current index const result = data.reduce(function (pV, cV, cI) { if (cV.some(function (obj) { return obj.status })) { pV.push(cI); } return pV; },[]); console.log(result);