Typeahead ngModel must be `undefined` for min-length="0" to work

[matthias-ccri]

Bug description:

What should happen:
When the attribute typeahead-min-length="0" is present, focusing on the field should trigger the results dropdown to display. This works only when the ngModel is set to undefined, but it does not work when it is set to null.

Plunkr:

https://plnkr.co/edit/dqqcVIGFcVFzvqn2fu4t?p=preview
This is the stock typeahead Plunkr, with only one line changed in example.js:
$scope.customSelected = null;

Versions

Angular: 1.5.8
UIBS: 2.2.0
Bootstrap: 3.3.7

[wesleycho]

This would be a breaking change - I'm not necessarily against this, but this could have unintended consequences.

[shyamal890]

I added a directive to solve the issue temporarily. It simply triggers input change on focus. However typeahead-min-length="0" implicitly means that typeahead should trigger on focus. Hope Angular-UI team solves this eventually.

app.directive('typeaheadShowOnFocus', function () {
    return {
        require: 'ngModel',
        link: function ($scope, element, attrs, ngModel) {
            element.bind('focus', function () {
                ngModel.$setViewValue();
                $(element).trigger('input');
                $(element).trigger('change');
            });
        }
    };
});

Plunker Example : https://plnkr.co/edit/ifaZMhsFaHrQZFOaIA0w?p=preview

[InFerYes]

I'm experiencing the same issue, that the dropdown doesn't show after clearing the ng-model in code. As soon as I enter anything (and clear via keyboard), the dropdown works again.

The above directive doesn't work for me.

Making sure the value binded to the ng-model is not null is a workaround.