Find the index of the final empty element in an array using AngularJS

Question

Find the index of the final empty element in an array using AngularJS

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 an array structure similar to the above examples. I am looking for assistance in extracting all records that appear after the last occurrence of "type":"". In this scenario, it should return the last 3 records from caseOne and 0 records from caseTwo, which essentially means all records after "type":"".

Your help is greatly appreciated.

Desired output

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

caseTwo = [];

javascript angularjs

Answer 1

Answer №1

Create a function called getEndIndex() that can be used to find the index of the last object in an array with a specific type: "". Using this index, you can then use the splice() method to extract 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 getEndIndex(caseArray){
  var endIndex;
  caseArray.forEach(function(obj, index){
    if(obj.type === ''){
      endIndex = index;
    }
  });
  return endIndex;
}

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

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

Alternatively, if your array is likely to have objects with type:'' at the end, you can search for the index starting from the last object in the 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 getEndIndex(caseArray){
  var i;
  for(i=caseArray.length-1; i>=0; i--){
   if(caseArray[i].type === ''){
      break;
    }
  }
  return i;
}

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

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

Answer 2

Create a function called getEndIndex() that can be used to find the index of the last object in an array with a specific type: "". Using this index, you can then use the splice() method to extract 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 getEndIndex(caseArray){
  var endIndex;
  caseArray.forEach(function(obj, index){
    if(obj.type === ''){
      endIndex = index;
    }
  });
  return endIndex;
}

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

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

Alternatively, if your array is likely to have objects with type:'' at the end, you can search for the index starting from the last object in the 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 getEndIndex(caseArray){
  var i;
  for(i=caseArray.length-1; i>=0; i--){
   if(caseArray[i].type === ''){
      break;
    }
  }
  return i;
}

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

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

Answer 3

Answer №2

How can retrieving array elements in this manner be beneficial? Instead of manually searching through an array for elements after a specific point, there may be a more efficient solution available. In any case, you are seeking code similar to:

// original data
const data = [
    {"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 index = Array
.from( data ) // Create a copy of the array to avoid altering the original when reversing.
.reverse() // Reverse the array so findIndex can be used instead of implementing findLastIndex.
.findIndex( entry => !entry.type ); // Determine the index of the first element without a type value.
const resultData = data.slice( data.length - index, data.length ); // Extract a portion of the original array.
console.log( resultData );

Answer 4

How can retrieving array elements in this manner be beneficial? Instead of manually searching through an array for elements after a specific point, there may be a more efficient solution available. In any case, you are seeking code similar to:

// original data
const data = [
    {"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 index = Array
.from( data ) // Create a copy of the array to avoid altering the original when reversing.
.reverse() // Reverse the array so findIndex can be used instead of implementing findLastIndex.
.findIndex( entry => !entry.type ); // Determine the index of the first element without a type value.
const resultData = data.slice( data.length - index, data.length ); // Extract a portion of the original array.
console.log( resultData );

Answer 5

Answer №3

To achieve this, you can follow these steps:
   
   let exampleArray = [
                    {"name":"Alice", "gender":"F","type":"Admin"},
                    {"name":"Bob", "gender":"M","type":""},
                    {"name":"Super Woman", "gender":"F","type":""},
                    {"name":"Spider Man", "gender":"M","type":""},
                    {"name":"Iron Man", "gender":"M","type":"User"},
                    {"name":"Black Widow", "gender":"F","type":"User"},
                    {"name":"Deadpool", "gender":"M","type":"Admin"}
                ];
                
                let modifiedArray = [];
                let indexCount = 0;
                
                for(let i=0; i<exampleArray.length; i++) {
                    if(exampleArray[i].type == ''){
                        indexCount++;
                    }
                }
                
                modifiedArray = exampleArray.splice(indexCount+1, exampleArray.length);
            console.log(modifiedArray);

Answer 6

To achieve this, you can follow these steps:
   
   let exampleArray = [
                    {"name":"Alice", "gender":"F","type":"Admin"},
                    {"name":"Bob", "gender":"M","type":""},
                    {"name":"Super Woman", "gender":"F","type":""},
                    {"name":"Spider Man", "gender":"M","type":""},
                    {"name":"Iron Man", "gender":"M","type":"User"},
                    {"name":"Black Widow", "gender":"F","type":"User"},
                    {"name":"Deadpool", "gender":"M","type":"Admin"}
                ];
                
                let modifiedArray = [];
                let indexCount = 0;
                
                for(let i=0; i<exampleArray.length; i++) {
                    if(exampleArray[i].type == ''){
                        indexCount++;
                    }
                }
                
                modifiedArray = exampleArray.splice(indexCount+1, exampleArray.length);
            console.log(modifiedArray);

Find the index of the final empty element in an array using AngularJS

Answer №1

Answer №2

Answer №3

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