I now have a working solution. There are 2 new directives which focus the field and automatically open the typeahead dropdown.
There is a working Plunker here.
app.js
(function () {
var secretEmptyKey = '[$empty$]'
angular.module('plunker', ['ui.bootstrap'])
.directive('focusMe', function($timeout, $parse) {
return {
//scope: true, // optionally create a child scope
link: function(scope, element, attrs) {
var model = $parse(attrs.focusMe);
scope.$watch(model, function(value) {
if(value === true) {
$timeout(function() {
element[0].focus();
});
}
});
}
};
})
.directive('emptyTypeahead', function () {
return {
require: 'ngModel',
link: function (scope, element, attrs, modelCtrl) {
// this parser run before typeahead's parser
modelCtrl.$parsers.unshift(function (inputValue) {
var value = (inputValue ? inputValue : secretEmptyKey); // replace empty string with secretEmptyKey to bypass typeahead-min-length check
modelCtrl.$viewValue = value; // this $viewValue must match the inputValue pass to typehead directive
return value;
});
// this parser run after typeahead's parser
modelCtrl.$parsers.push(function (inputValue) {
return inputValue === secretEmptyKey ? '' : inputValue; // set the secretEmptyKey back to empty string
});
}
}
})
.controller('TypeaheadCtrl', function($scope, $http, $timeout) {
$scope.selected = undefined;
$scope.states = ['Alabama', 'Alaska', 'Arizona', 'Arkansas', 'California', 'Colorado', 'Connecticut', 'Delaware', 'Florida', 'Georgia', 'Hawaii', 'Idaho', 'Illinois', 'Indiana', 'Iowa', 'Kansas', 'Kentucky', 'Louisiana', 'Maine', 'Maryland', 'Massachusetts', 'Michigan', 'Minnesota', 'Mississippi', 'Missouri', 'Montana', 'Nebraska', 'Nevada', 'New Hampshire', 'New Jersey', 'New Mexico', 'New York', 'North Dakota', 'North Carolina', 'Ohio', 'Oklahoma', 'Oregon', 'Pennsylvania', 'Rhode Island', 'South Carolina', 'South Dakota', 'Tennessee', 'Texas', 'Utah', 'Vermont', 'Virginia', 'Washington', 'West Virginia', 'Wisconsin', 'Wyoming'];
$scope.opened = false;
$scope.stateComparator = function (state, viewValue) {
return viewValue === secretEmptyKey || (''+state).toLowerCase().indexOf((''+viewValue).toLowerCase()) > -1;
};
$scope.onFocus = function (e) {
$timeout(function () {
$(e.target).trigger('input');
});
};
$scope.open = function() {
$scope.opened = true;
}
$scope.close = function() {
$scope.opened = false;
}
});
}());
HTML View
<!DOCTYPE html>
<html ng-app="plunker">
<head>
<link href="//netdna.bootstrapcdn.com/bootstrap/3.1.1/css/bootstrap.min.css" rel="stylesheet" />
<link href="style.css" rel="stylesheet" />
<script src="//cdnjs.cloudflare.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="//ajax.googleapis.com/ajax/libs/angularjs/1.2.2/angular.js"></script>
<script src="ui-bootstrap-tpls-0.10.0.js"></script>
<script src="app.js"></script>
</head>
<body>
<div class="container-fluid" ng-controller="TypeaheadCtrl">
<h4>Typeahead dropdown opens automatically</h4>
<p>2 directives automatically focus on the field and show the dropdown.
<br />
<br />
<button class="btn btn-default" ng-show="!opened" ng-click="open()">Open Input and show typeahead!</button>
<button class="btn btn-default" ng-show="opened" ng-click="close()">Close Input</button>
<br />
<br />
<input type="text" focus-me="opened" ng-focus="onFocus($event)" ng-show="opened" ng-trim="false" ng-model="selected" empty-typeahead typeahead="state for state in states | filter:$viewValue:stateComparator" class="form-control" />
<br />
</p>
<pre ng-show="opened">Model: {{selected | json}}</pre>
</div>
</body>
</html>
This solution was posted in response to my question here:
Angular JS - Automatically focus input and show typeahead dropdown - ui.bootstrap.typeahead
