Locate the position of an element within an array using AngularJS

Question

Locate the position of an element within an array using AngularJS

Consider the following array:

  $scope.records = [
    {
      "Name" : "Alfreds Futterkiste",
      "Country" : "Germany"
    },
    {
      "Name" : "Berglunds snabbköp",
      "Country" : "Sweden"
    },
    {
      "Name" : "Centro comercial Moctezuma",
      "Country" : "Mexico"
    },
    {
      "Name" : "Ernst Handel",
      "Country" : "Austria"
    }
  ];

How can you determine the index value of an object? For example, for the object with "Country" : "Austria", the index is 3.

javascript angularjs arrays

Answer 1

Answer №1

If you're looking to find the index of an element in an array, you can utilize the Array.findIndex method in modern browsers. However, this method is not supported in Internet Explorer, only in Edge.

let $scope = {};

$scope.records = [
    {
      "Name" : "Alfreds Futterkiste",
      "Country" : "Germany"
    },
    {
      "Name" : "Berglunds snabbköp",
      "Country" : "Sweden"
    },
    {
      "Name" : "Centro comercial Moctezuma",
      "Country" : "Mexico"
    },
    {
      "Name" : "Ernst Handel",
      "Country" : "Austria"
    }
];

let index = $scope.records.findIndex(record => record.Country === "Austria");

console.log(index); // 3

To ensure compatibility with IE9 and above, you can opt for using Array.some instead

var $scope = {};

$scope.records = [{
  "Name": "Alfreds Futterkiste",
  "Country": "Germany"
}, {
  "Name": "Berglunds snabbköp",
  "Country": "Sweden"
}, {
  "Name": "Centro comercial Moctezuma",
  "Country": "Mexico"
}, {
  "Name": "Ernst Handel",
  "Country": "Austria"
}];

var index = -1;

$scope.records.some(function(obj, i) {
  return obj.Country === "Austria" ? index = i : false;
});

console.log(index);

Answer 2

If you're looking to find the index of an element in an array, you can utilize the Array.findIndex method in modern browsers. However, this method is not supported in Internet Explorer, only in Edge.

let $scope = {};

$scope.records = [
    {
      "Name" : "Alfreds Futterkiste",
      "Country" : "Germany"
    },
    {
      "Name" : "Berglunds snabbköp",
      "Country" : "Sweden"
    },
    {
      "Name" : "Centro comercial Moctezuma",
      "Country" : "Mexico"
    },
    {
      "Name" : "Ernst Handel",
      "Country" : "Austria"
    }
];

let index = $scope.records.findIndex(record => record.Country === "Austria");

console.log(index); // 3

To ensure compatibility with IE9 and above, you can opt for using Array.some instead

var $scope = {};

$scope.records = [{
  "Name": "Alfreds Futterkiste",
  "Country": "Germany"
}, {
  "Name": "Berglunds snabbköp",
  "Country": "Sweden"
}, {
  "Name": "Centro comercial Moctezuma",
  "Country": "Mexico"
}, {
  "Name": "Ernst Handel",
  "Country": "Austria"
}];

var index = -1;

$scope.records.some(function(obj, i) {
  return obj.Country === "Austria" ? index = i : false;
});

console.log(index);

Answer 3

Answer №2

If you want to find a specific item in an array, you can utilize the array.findIndex method:

var items = [{
  "Name": "Alfreds Futterkiste",
  "Country": "Germany"
}, {
  "Name": "Berglunds snabbköp",
  "Country": "Sweden"
}, {
  "Name": "Centro comercial Moctezuma",
  "Country": "Mexico"
}, {
  "Name": "Ernst Handel",
  "Country": "Austria"
}];
var searchCountry = "Austria";
var index = items.findIndex(item => item.Country === searchCountry);
console.log(index)

Note: If you are interested, you can learn more about array.findIndex on the Mozilla Developer Network website as it is part of ES6.

Answer 4

If you want to find a specific item in an array, you can utilize the array.findIndex method:

var items = [{
  "Name": "Alfreds Futterkiste",
  "Country": "Germany"
}, {
  "Name": "Berglunds snabbköp",
  "Country": "Sweden"
}, {
  "Name": "Centro comercial Moctezuma",
  "Country": "Mexico"
}, {
  "Name": "Ernst Handel",
  "Country": "Austria"
}];
var searchCountry = "Austria";
var index = items.findIndex(item => item.Country === searchCountry);
console.log(index)

Note: If you are interested, you can learn more about array.findIndex on the Mozilla Developer Network website as it is part of ES6.

Answer 5

Answer №3

Try employing the findIndex function:
   let index = $scope.records.findIndex(item => item.Country === 'Austria')

Answer 6

Try employing the findIndex function:
   let index = $scope.records.findIndex(item => item.Country === 'Austria')

Answer 7

Answer №4

const getCountryIndex = (country) => {
    let foundCountry = $scope.records.find((item) => {
        return item.Country === country;
    });
    return $scope.records.indexOf(foundCountry);
}

Answer 8

const getCountryIndex = (country) => {
    let foundCountry = $scope.records.find((item) => {
        return item.Country === country;
    });
    return $scope.records.indexOf(foundCountry);
}

Answer 9

Answer №5

To retrieve a list of countries and then search for a specific country, you can try:

$scope.records.map((item) => { return item.Country;}).indexOf('Austria')

The issue with the code above is that it loops through each element to create a map before finding the index. A more efficient approach would be using a simple for loop like this:

var index = (arr, k, v) => { 
   var i = -1;len = (arr || []).length;  
   for (i = 0; i < len; i++) { 
     if (arr[i][k] === v) 
       return i;
   }
   return -1;
}

I have come across many findIndex solutions. It's worth noting that the FindIndex method is part of ECMAScript 6 and may not be supported in all JavaScript implementations yet according to MDN.

If you prefer using the polyfill for findIndex(https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/findIndex) along with other suggested findIndex solutions. Alternatively, if you choose not to use the polyfill, you can opt for the map and indexOf method I recommended.

Answer 10

To retrieve a list of countries and then search for a specific country, you can try:

$scope.records.map((item) => { return item.Country;}).indexOf('Austria')

The issue with the code above is that it loops through each element to create a map before finding the index. A more efficient approach would be using a simple for loop like this:

var index = (arr, k, v) => { 
   var i = -1;len = (arr || []).length;  
   for (i = 0; i < len; i++) { 
     if (arr[i][k] === v) 
       return i;
   }
   return -1;
}

I have come across many findIndex solutions. It's worth noting that the FindIndex method is part of ECMAScript 6 and may not be supported in all JavaScript implementations yet according to MDN.

If you prefer using the polyfill for findIndex(https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/findIndex) along with other suggested findIndex solutions. Alternatively, if you choose not to use the polyfill, you can opt for the map and indexOf method I recommended.

Answer 11

Answer №6

I've implemented this method and it's working perfectly:

Array.prototype.getIndexByValue = function (key, value) {
        for (var i = 0, len=this.length; i <len; i++) {
            if (this[i][key]) {
                if (this[i][key] === value) {
                    return i;
                }
            }
        }
        return -1;
    };

var data = [{
  "Name": "Alfreds Futterkiste",
  "Country": "Germany"
}, {
  "Name": "Berglunds snabbköp",
  "Country": "Sweden"
}, {
  "Name": "Centro comercial Moctezuma",
  "Country": "Mexico"
}, {
  "Name": "Ernst Handel",
  "Country": "Austria"
}];

var index = data.getIndexByValue('Country','Austria');
console.log(index)//will print 3

Answer 12

I've implemented this method and it's working perfectly:

Array.prototype.getIndexByValue = function (key, value) {
        for (var i = 0, len=this.length; i <len; i++) {
            if (this[i][key]) {
                if (this[i][key] === value) {
                    return i;
                }
            }
        }
        return -1;
    };

var data = [{
  "Name": "Alfreds Futterkiste",
  "Country": "Germany"
}, {
  "Name": "Berglunds snabbköp",
  "Country": "Sweden"
}, {
  "Name": "Centro comercial Moctezuma",
  "Country": "Mexico"
}, {
  "Name": "Ernst Handel",
  "Country": "Austria"
}];

var index = data.getIndexByValue('Country','Austria');
console.log(index)//will print 3

Answer 13

Answer №7

To iterate through a JSON array using a for-in loop, you can implement the following code snippet

for(i in records) {
if(records[i].country=="Austria") 
console.log("The index is: "+ parseInt(i)); // display index
}

Answer 14

To iterate through a JSON array using a for-in loop, you can implement the following code snippet

for(i in records) {
if(records[i].country=="Austria") 
console.log("The index is: "+ parseInt(i)); // display index
}

Locate the position of an element within an array using AngularJS

Answer №1

Answer №2

Answer №3

Answer №4

Answer №5

Answer №6

Answer №7

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