Make For loop a Function

Question

I have created a code that checks the existence of an specific string inside array-object:

array = [{'grade': 'two'}, {'grade': 'three'}, {'grade': 'four'}];

for (var i = 0; i < array.length; i++) {  
    if (array[i].grade === 'four'){      
        remIndex = [i]; 
        break;     
    }  
}

console.log(remIndex);

This code works.

But when i tried to convert it into a function it won't work:

function getARRAYINDEX( array, callOBJ, findSTRING){

  for (var i = 0; i < array.length; i++) {
    if (array[i].callOBJ === findSTRING){
        remIndex = [i]; 
        break;
    }    
  }

  return remIndex;  
}

31piy · Accepted Answer · 2018-07-27 04:34:14Z

2

If you have the key name in a variable, you need to use the [] notation to access the property in the object. Replace this:

if (array[i].callOBJ === findSTRING){

with this:

if (array[i][callOBJ] === findSTRING){

Please do read this documentation to know more about working with objects.

answered Jul 27, 2018 at 4:34

31piy

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Comments

Zeeshan Tariq · Accepted Answer · 2018-07-27 04:40:21Z

0

You need to define remIndex, if it doesn't come in the if block remIndex will be undefined and on return statement it will throw an exception. You can do it like this:

function getARRAYINDEX( array, callOBJ, findSTRING){
var remIndex;
  for (var i = 0; i < array.length; i++) {

    if (array[i][callOBJ] === findSTRING){

        remIndex = [i]; 
        break;

    }

  }
  return remIndex;
}

answered Jul 27, 2018 at 4:40

Zeeshan Tariq

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Comments

sjahan · Accepted Answer · 2018-07-27 04:42:01Z

0

When the property name is dynamic, you have to use [].

array[i][callOBJ]

and not

array[i].callOBJ

In the line above, callOBJ won't be evaluated and the code will try to get the property callOBJ and not the name stored in callOBJ.

const array = [{'grade': 'two'}, {'grade': 'three'}, {'grade': 'four'}];


function getARRAYINDEX( array, callOBJ, findSTRING){
  for (var i = 0; i < array.length; i++) {
    if (array[i][callOBJ] === findSTRING){
        remIndex = [i];
        break;
    }
  }
  return remIndex;
}

console.log(getARRAYINDEX(array, 'grade', 'three'));

By the way, you can achieve the same thing with findIndex ;)

const array = [{'grade': 'two'}, {'grade': 'three'}, {'grade': 'four'}];


function getARRAYINDEX( array, callOBJ, findSTRING){
  return [array.findIndex(item => item[callOBJ] === findSTRING)];
}

console.log(getARRAYINDEX(array, 'grade', 'three'));

edited Jul 27, 2018 at 4:42

answered Jul 27, 2018 at 4:36

sjahan

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1 Comment

Tramyer Over a year ago

i'm kind used to use like this way array[i].grade etc...i seldom use the bracket version when calling object prop.. anyways thanks mate

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