CODEWITHSUNDEEP
javascriptarraysmultidimensional-array
Brian Polanco
Brian Polanco

Reputation: 48

How can I find the index of a 2d array of objects in javascript

So, what I'm trying to get is the index of a 2d array of objects, let's say I have the following

const arr = [
  [{id: 1}, {id:2}],
  [{id:3},{id:4},{id:5}]
  ]

If I'd want to get the index where id=3 it would be arr[1][0], Is there any way to achieve this using vanilla JS or any helper library?

Upvotes: 0

Views: 265

Answers (4)

Neeraj Kumar
Neeraj Kumar

Reputation: 456

 const arr = [
  [{id: 1}, {id:2}],
  [{id:3},{id:4},{id:5}]
  ];
  
 
 
function getIndex(arr, value){
 
 let rowIndex = null;
 let valueIndex = null;
 
 arr.forEach(( nestedArray, index) => {
    
  if(!valueIndex) rowIndex = index;
  
  nestedArray.every((val, valIndex) => {
    if(val.id === value) {
        valueIndex = valIndex;
      return false
    }
    return true;
  });
  
 })
 
return {
rowIndex, 
valueIndex
} 
 
}


console.log(getIndex(arr, 3))

Upvotes: 0

Marcin Wanago
Marcin Wanago

Reputation: 653

You can achieve this by nesting two for loops.

function findNestedIndices(array, id) {
  let i;
  let j;

  for (i = 0; i < array.length; ++i) {
    const nestedArray = array[i];
    for (j = 0; j < nestedArray.length; ++j) {
      const object = nestedArray[j];
      if (object.id === id) {
        return { i, j };
      }
    }
  }
  return {};
}

const array = [
  [{id: 1}, {id:2}],
  [{id:3},{id:4},{id:5}]
];

const { i, j } = findNestedIndices(array, 3);

console.log(i, j); // 1, 0

Upvotes: 1

Balastrong
Balastrong

Reputation: 4464

const arr = [
    [{id: 1}, {id:2}],
    [{id:3},{id:4},{id:5}]
  ];
  
let searchIndex = 3;

let x = arr.findIndex(sub => sub.find(el => el.id == searchIndex));
let y = arr[x].findIndex(el => el.id == searchIndex);

console.log(x, y)

Upvotes: 1

ray
ray

Reputation: 27245

Might be a more efficient way to do it, but you could accomplish this via array.findIndex:

const test = [
  [{id: 1}, {id:2}],
  [{id:3},{id:4},{id:5}]
];

function find(arr, id) {
  const firstIndex = arr.findIndex(entry => entry.some(({id: x}) => x === id));
  if (firstIndex > -1) {
    const secondIndex = arr[firstIndex].findIndex(({ id: x }) => x === id );
    return [firstIndex, secondIndex];
  }
}

console.log(find(test, 2)); // [0, 1]
console.log(find(test, 4)); // [1, 1]
console.log(find(test, 5)); // [1, 2]

Upvotes: 1

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