Function parseOptionsExpression

test/angular/1.6/angular.js:31079–31233

(optionsExp, selectElement, scope)

var ngOptionsDirective = ['$compile', '$document', '$parse', function($compile, $document, $parse) {

  function parseOptionsExpression(optionsExp, selectElement, scope) {

    var match = optionsExp.match(NG_OPTIONS_REGEXP);
    if (!(match)) {
      throw ngOptionsMinErr('iexp',
        'Expected expression in form of ' +
        '\'_select_ (as _label_)? for (_key_,)?_value_ in _collection_\'' +
        ' but got \'{0}\'. Element: {1}',
        optionsExp, startingTag(selectElement));
    }

    // Extract the parts from the ngOptions expression

    // The variable name for the value of the item in the collection
    var valueName = match[5] || match[7];
    // The variable name for the key of the item in the collection
    var keyName = match[6];

    // An expression that generates the viewValue for an option if there is a label expression
    var selectAs = / as /.test(match[0]) && match[1];
    // An expression that is used to track the id of each object in the options collection
    var trackBy = match[9];
    // An expression that generates the viewValue for an option if there is no label expression
    var valueFn = $parse(match[2] ? match[1] : valueName);
    var selectAsFn = selectAs && $parse(selectAs);
    var viewValueFn = selectAsFn || valueFn;
    var trackByFn = trackBy && $parse(trackBy);

    // Get the value by which we are going to track the option
    // if we have a trackFn then use that (passing scope and locals)
    // otherwise just hash the given viewValue
    var getTrackByValueFn = trackBy ?
                              function(value, locals) { return trackByFn(scope, locals); } :
                              function getHashOfValue(value) { return hashKey(value); };
    var getTrackByValue = function(value, key) {
      return getTrackByValueFn(value, getLocals(value, key));
    };

    var displayFn = $parse(match[2] || match[1]);
    var groupByFn = $parse(match[3] || '');
    var disableWhenFn = $parse(match[4] || '');
    var valuesFn = $parse(match[8]);

    var locals = {};
    var getLocals = keyName ? function(value, key) {
      locals[keyName] = key;
      locals[valueName] = value;
      return locals;
    } : function(value) {
      locals[valueName] = value;
      return locals;
    };


    function Option(selectValue, viewValue, label, group, disabled) {
      this.selectValue = selectValue;
      this.viewValue = viewValue;
      this.label = label;