AngularJS - get index of last blank element from array

Question

var caseOne = [
    {"name":"Felicity", "gender":"F", ...   ... ,"type":"Admin"},
    {"name":"Tony", "gender":"M", ...   ... ,"type":""},
    .
    .
    .
    .
    {"name":"Super Man", "gender":"M", ...   ... ,"type":""},
    {"name":"Wonder Women", "gender":"F", ...   ... ,"type":""},
    {"name":"Hulk", "gender":"M", ...   ... ,"type":"User"},
    {"name":"Loky", "gender":"M", ...   ... ,"type":"User"},
    {"name":"Thore", "gender":"M", ...   ... ,"type":"Admin"}
];

var caseTwo = [
    {"name":"Felicity", "gender":"F", ...   ... ,"type":"Admin"},
    {"name":"Tony", "gender":"M", ...   ... ,"type":""},
    .
    .
    .
    .
    {"name":"Super Man", "gender":"M", ...   ... ,"type":""},
    {"name":"Wonder Women", "gender":"F", ...   ... ,"type":""},
    {"name":"Hulk", "gender":"M", ...   ... ,"type":"User"},
    {"name":"Loky", "gender":"M", ...   ... ,"type":"User"},
    {"name":"Thore", "gender":"M", ...   ... ,"type":"Admin"},
    {"name":"Bat man", "gender":"M", ...   ... ,"type":""}
];

I have this kind of array. I want all records after lastIndexOf "type":"", means From cansOne it'll return last 3 record and from caseTwo it'll return 0 record. in short all records after "type":"". Can anyone help.

Thanks in advance.

Expected output

caseOne = [
    {"name":"Hulk", "gender":"M", ...   ... ,"type":"User"},
    {"name":"Loky", "gender":"M", ...   ... ,"type":"User"},
    {"name":"Thore", "gender":"M", ...   ... ,"type":"Admin"}
];

caseTwo = [];

@Parth Raval, I want last all records which has type. means if last record has type:"" then it return 0 or if third last record has type:"" then it'll return last two records. — Vipul Solanki
– Vipul Solanki, Commented Apr 27, 2018 at 11:46
@VipulSolanki find the index and splice it. Check the answer — Ankit Agarwal
– Ankit Agarwal, Commented Apr 27, 2018 at 11:51

Ankit Agarwal · Accepted Answer · 2018-04-27 12:00:44Z

3

Create a reusable function getIndex() that will take a array parameter and give you the last index of the object with type: "". Using this index you can splice() the result and get the desired output

var caseOne = [
    {"name":"Felicity", "gender":"F" ,"type":"Admin"},
    {"name":"Tony", "gender":"M","type":""},
    {"name":"Super Man", "gender":"M","type":""},
    {"name":"Wonder Women", "gender":"F" ,"type":""},
    {"name":"Hulk", "gender":"M","type":"User"},
    {"name":"Loky", "gender":"M" ,"type":"User"},
    {"name":"Thore", "gender":"M" ,"type":"Admin"}
];

var caseTwo = [
    {"name":"Felicity", "gender":"F" ,"type":"Admin"},
    {"name":"Tony", "gender":"M" ,"type":""},
    {"name":"Super Man", "gender":"M" ,"type":""},
    {"name":"Wonder Women", "gender":"F","type":""},
    {"name":"Hulk", "gender":"M","type":"User"},
    {"name":"Loky", "gender":"M","type":"User"},
    {"name":"Thore", "gender":"M","type":"Admin"},
    {"name":"Bat man", "gender":"M","type":""}
];

function getIndex(caseArray){
  var arrayIndex;
  caseArray.forEach(function(caseOneObj, index){
    if(caseOneObj.type === ''){
      arrayIndex = index;
    }
  });
  return arrayIndex;
}

var index = getIndex(caseOne);
var resultCaseOne = caseOne.splice(index+1, caseOne.length);
console.log('-----caseOne-----');
console.log(resultCaseOne);

index = getIndex(caseTwo);
var resultCaseTwo = caseTwo.splice(index+1, caseTwo.length);
console.log('-----caseTwo-----');
console.log(resultCaseTwo);

But, if you have array of objects that are most likely to have type:'' at the last of the array then you can search for that index starting from the last object of that array, like this:

var caseOne = [
    {"name":"Felicity", "gender":"F" ,"type":"Admin"},
    {"name":"Tony", "gender":"M","type":""},
    {"name":"Super Man", "gender":"M","type":""},
    {"name":"Wonder Women", "gender":"F" ,"type":""},
    {"name":"Hulk", "gender":"M","type":"User"},
    {"name":"Loky", "gender":"M" ,"type":"User"},
    {"name":"Thore", "gender":"M" ,"type":"Admin"}
];

var caseTwo = [
    {"name":"Felicity", "gender":"F" ,"type":"Admin"},
    {"name":"Tony", "gender":"M" ,"type":""},
    {"name":"Super Man", "gender":"M" ,"type":""},
    {"name":"Wonder Women", "gender":"F","type":""},
    {"name":"Hulk", "gender":"M","type":"User"},
    {"name":"Loky", "gender":"M","type":"User"},
    {"name":"Thore", "gender":"M","type":"Admin"},
    {"name":"Bat man", "gender":"M","type":""}
];

function getIndex(caseArray){
  var i;
  for(i=caseArray.length-1; i>0; i--){
   if(caseArray[i].type === ''){
      break;
    }
  }
  return i;
}

var index = getIndex(caseOne);
var resultCaseOne = caseOne.splice(index+1, caseOne.length);
console.log('-----caseOne-----');
console.log(resultCaseOne);

index = getIndex(caseTwo);
var resultCaseTwo = caseTwo.splice(index+1, caseTwo.length);
console.log('-----caseTwo-----');
console.log(resultCaseTwo);

edited Apr 27, 2018 at 12:00

answered Apr 27, 2018 at 11:51

Ankit Agarwal

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8 Comments

Panos K Over a year ago

we could change forEach to iterate from the end? and return downwards records this wouldnt be much faster?

Ankit Agarwal Over a year ago

It depends. What if the type:'' is in first index of array with size 1000. At this time it should loop over 999 records. Both scenario is same, from last or from first. You cannot actually say this is better than that. And we need the index of the last element so both can be opted @PanosK

Ankit Agarwal Over a year ago

@PanosK your point was useful. I edited my answer to include that

Vipul Solanki Over a year ago

Thanks, exactly I want like your second snippet. both are help full. @Ankit.

Ankit Agarwal Over a year ago

@VipulSolanki glad to help you

|

Shilly · Accepted Answer · 2018-04-27 12:03:01Z

1

What will getting those array elements this way solve? Since there's propably a better way than searching through an array to find everything after a certain element. Anyways, you;re looking for code like:

// source data
const source = [
    {"name":"Felicity", "gender":"F", "type":"Admin"},
    {"name":"Tony", "gender":"M", "type":""},
    {"name":"Super Man", "gender":"M", "type":""},
    {"name":"Wonder Women", "gender":"F", "type":""},
    {"name":"Hulk", "gender":"M", "type":"User"},
    {"name":"Loky", "gender":"M", "type":"User"},
    {"name":"Thore", "gender":"M", "type":"Admin"}
];
const lastIndex = Array
	.from( source ) // Clone the array so reversing does not affect the source.
	.reverse() // Reverse the array so we can use findIndex instead of writing findLastIndex ourselves.
	.findIndex( entry => !entry.type ); // Get the index of the first element that has no type.
const result = source.slice( source.length - lastIndex, source.length ); // Slice the orginal array.
console.log( result );

answered Apr 27, 2018 at 12:03

Shilly

8,5991 gold badge21 silver badges24 bronze badges

4 Comments

Ankit Agarwal Over a year ago

There are two arrays for OP and using this code is duplicated for both the arrays. This cannot be taken as a optimal solution

Shilly Over a year ago

Just wrapping it in a function and returning the sliced part will solve that. Anyways, I was trying to help, not diss your own solution if that's how it came across. Can't take back my upvote on your answer now anymore though.

Ankit Agarwal Over a year ago

If you really meant to answer, answer in a appropriate way and make it complete. I hear incompleteness from your previous comment. Anyways I also don't want to diss

Shilly Over a year ago

I'll go get us some tequilas and i'll reread the answering rules.

kaushlendras · Accepted Answer · 2018-04-27 12:05:00Z

You can do it like this:

   var caseOne = [
                    {"name":"Felicity", "gender":"F","type":"Admin"},
                    {"name":"Tony", "gender":"M","type":""},
                    {"name":"Super Man", "gender":"M","type":""},
                    {"name":"Wonder Women", "gender":"F","type":""},
                    {"name":"Hulk", "gender":"M","type":"User"},
                    {"name":"Loky", "gender":"M","type":"User"},
                    {"name":"Thore", "gender":"M","type":"Admin"}
                ];
                var result =[];
                var counterIndex = 0;
                for(var i=0; i<caseOne.length; i++) {
                    if(caseOne[i].type == '')
                    counterIndex++;
                }
                result = caseOne.splice(counterIndex+1, caseOne.length);
            console.log(result);

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