AngularJS ng-options create range

Question

I am trying to create a select element that has a list of numbers 1 to pages where pages is a variable that is the number of pages I have. What i don't know how to do is to structure the ng-options expression so that it will give me the numbers I need. Here is what I have so far

<select ng-model="page" ng-options="???"></select>

what do I need to put in the ng-options expression in order for it to create my select like

<select>
    <option value="1">1</option>
    ...
    <option value="35">35</option>
</select>

do I need to create a function that returns an array of numbers and use it in there somehow or is there an easier way to do this?

any help would be greatly appreciated.

Thanks

EDIT

After posting my question i figured out one way to do it by creating a function called Range in my controller that takes two numbers and returns an array with all the values in that range.

$scope.Range = function(start, end) {
    var result = [];
    for (var i = start; i <= end; i++) {
        result.push(i);
    }
    return result;
};

then in the HTML I did

<select ng-name="page" ng-options="page for page in Range(1, pages)"></select> 

Is this the simplest way to do this or is there a better way?

Answer 1

Your way works fine. Another option that came to my head is to use a filter, so you don't have to pollute your controller with Range.

JS:

var myApp = angular.module('myApp', []);
myApp.filter('range', function() {
  return function(input, min, max) {
    min = parseInt(min); //Make string input int
    max = parseInt(max);
    for (var i=min; i<max; i++)
      input.push(i);
    return input;
  };
});

HTML:

<select ng-model="page" ng-options="n for n in [] | range:1:30"></select>

Example: http://jsfiddle.net/N3ZVp/1/

P.S. in your example in your main post, you didn't put var in front of i. So i is declared as a global variable in your example.

Answer 2

Another solution to keep it all in your template:

<select>
  <option ng-repeat="n in [].constructor(10) track by $index+1">{{$index+1}}</option>
</select>

Answer 3

Please add ng-model, like below

<select ng-model="test" ng-options="n for n in [] | range:1:30"></select>

After this your example will work in jsfiddle

Answer 4

another approach without a for loop is this:

controller:

 $scope.arr = [];
 $scope.arr.length = count;

view binding:

 ng-options="arr.indexof(i) for i in arr"

Answer 5

Andy's solution is great, however the range cannot go backwards. Here's the improved version:

/* 
 * Creates a range
 * Usage example: <option ng-repeat="y in [] | range:1998:1900">{{y}}</option>
 */
myApp.filter('range', function() {
  return function(input, start, end) {    
    start = parseInt(start);
    end = parseInt(end);
    var direction = (start <= end) ? 1 : -1;
    while (start != end) {
        input.push(start);
        start += direction;
    }
    return input;
  };
});

Answer 6

Piggybacking on martynas' answer. I modified it to include the last value in the range:

/*
 * Creates a range
 * Usage example: <option ng-repeat="y in [] | range:1998:1900">{{y}}</option>
 */

.filter('range', function () {
    return function (input, start, end) {
        var direction;

        start = parseInt(start);
        end = parseInt(end);

        if (start === end) { return [start]; }

        direction = (start <= end) ? 1 : -1;

        while (start != end) {
            input.push(start);

            if (direction < 0 && start === end + 1) {
                input.push(end);
            }

            if (direction > 0 && start === end - 1) {
                input.push(end);
            }

            start += direction;
        }

        return input;
    };
});

Answer 7

In CoffeeScript:

app.filter 'range', ->
  (input, min, max) ->
    input.push(i) for i in [parseInt(min)..parseInt(max)]

And the HTML:

<select ng-options="n for n in [] | range:1:30"></select>

Here is the gist with the Javascript

Answer 8

If you want to add a placeholder in select, then use below given solution. You need to first define the filter like this.

<select>
    <option value="">-- Birth Year --</option>
    <option ng-repeat="n in [] | range:1900:2000">{{n}}</option>
</select>