How do I check particularly using AngularJS if an array has duplicate values?
If more than 1 element of the same exist, then return true. Otherwise, return false.
$scope.intArray = [5, 11, 17, 53] // return false because no duplicates exist
$scope.intArray = [5, 11, 17, 5] // return true because duplicaets exist
If you have an ES2015 environment (as of this writing: io.js, IE11, Chrome, Firefox, WebKit nightly), then the following will work, and will be fast (viz. O(n)):
function hasDuplicates(array) {
return (new Set(array)).size !== array.length;
}
Otherwise:
function hasDuplicates(array) {
var valuesSoFar = Object.create(null);
for (var i = 0; i < array.length; ++i) {
var value = array[i];
if (value in valuesSoFar) {
return true;
}
valuesSoFar[value] = true;
}
return false;
}
Just sort the array and then run through it and see if the next index is the same as the current.
$scope.intArray = [5, 11, 17, 5];
checkDupes($scope.intArray);
function checkDupes(array)
{
array.sort(); // use whatever sort you want
for (var i = 0; o < array.length -1; i++)
{
if (array[i+1] == array[i])
{
return true;
}
}
return false;
}
http://codepen.io/anon/pen/xZrrXG?editors=101
Created the hasDuplicate as a scope method which could be easily used in your html if need-be.
var app = angular.module('myapp', []);
app.controller('mycontroller', ['$scope', function($scope) {
$scope.intArray = [5, 11, 17, 5];
$scope.hasDuplicate = function(data) {
for (var i = 0; i < data.length; i++) {
for (var x = i + 1; x < data.length; x++) {
if (data[i] == data[x]) {
return true;
}
}
}
return false;
};
}]);
You could use lodash library, you could find it very handy sometimes. And implement it like mentioned here: https://stackoverflow.com/a/28461122/4059878
