Get Index of Array Containing Value from Multi-dimensional Array in JS

Question

Suppose I have a multi dimensional array in JavaScript:

var arr = [
    ['cat','23','5123'],
    ['dog','53','522'],
    ['bird','335','512'],
    ['horse','853','152'], 
    ['monkey','13','5452']
];

And I want to get the index of the array in arr that contains horse in the first index (output should be 3).

I can do this in the following way:

var index_i_need;

for(var i in arr){

    if(arr[i][0]==='horse') {

        index_i_need = i;
        break;
    }
}

console.log(index_i_need);  // 3
console.log(arr[index_i_need]); // ['horse','853','152']

But this isnt scaleable.

Id like to have some more direct method like indexOf(), for instance.

I know findIndex() takes a callback function but I havent been able to apply it correctly.

Any suggestions?

arr.findIndex(sa => sa[0] === "horse");

Redu
– Redu

2017-05-27 07:07:54 +00:00
Commented May 27, 2017 at 7:07 — Redu
– Redu, Commented May 27, 2017 at 7:07

julian soro · Accepted Answer · 2017-05-26 22:07:22Z

2

You can use a dynamic find function, findByAnimal, to use in findIndex

function findByAnimal(animal) {
  return function(innerArr){
    return innerArr[0] === animal
  }
}

arr.findIndex( findByAnimal('horse') )

The way findIndex works is each item in arr is passed into the callback, the first "truthy" return value from callback will yield the index, or -1 if no items return truthy.

edited May 26, 2017 at 22:07

answered May 26, 2017 at 22:04

julian soro

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2 Comments

julian soro Over a year ago

Thanks @James, I quickly realized the same and updated the answer

julian soro Over a year ago

@yevg if you found this useful, feel free to mark as answered or provide feedback. thanks

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