angularjs - 如何创建 AngularJS jQueryUI 自动完成指令

Question

我正在尝试创建一个使用 jQueryUI 的自动完成小部件的自定义指令。我希望这尽可能具有声明性。这是所需的标记:

<div>
    <autocomplete ng-model="employeeId" url="/api/EmployeeFinder" label="{{firstName}} {{surname}}" value="id" />
</div>

因此，在上面的示例中，我希望指令对指定的 url 执行 AJAX 调用，并在返回数据时，显示根据文本框中结果的表达式计算的值，并将 id 属性设置为员工 ID。这是我对指令的尝试。

app.directive('autocomplete', function ($http) {
    return {
        restrict: 'E',
        replace: true,
        template: '<input type="text" />',
        require: 'ngModel',

        link: function (scope, elem, attrs, ctrl) {
            elem.autocomplete({
                source: function (request, response) {
                    $http({
                    url: attrs.url,
                    method: 'GET',
                    params: { term: request.term }
                })
                .then(function (data) {
                    response($.map(data, function (item) {
                        var result = {};

                        result.label = item[attrs.label];
                        result.value = item[attrs.value];

                        return result;
                    }))
                });
                },

                select: function (event, ui) {                    
                    ctrl.$setViewValue(elem.val(ui.item.label));                    

                    return false;
                }
            });
        }
    }    
});

所以，我有两个问题 - 如何评估 label 属性中的表达式以及如何将属性从 value 属性设置为我的范围内的 ngModel 。

Answer 1

这是我更新的指令

(function () {
'use strict';

angular
    .module('app')
    .directive('myAutocomplete', myAutocomplete);

myAutocomplete.$inject = ['$http', '$interpolate', '$parse'];
function myAutocomplete($http, $interpolate, $parse) {

    // Usage:

    //  For a simple array of items
    //  <input type="text" class="form-control" my-autocomplete url="/some/url" ng-model="criteria.employeeNumber"  />

    //  For a simple array of items, with option to allow custom entries
    //  <input type="text" class="form-control" my-autocomplete url="/some/url" allow-custom-entry="true" ng-model="criteria.employeeNumber"  />

    //  For an array of objects, the label attribute accepts an expression.  NgModel is set to the selected object.
    //  <input type="text" class="form-control" my-autocomplete url="/some/url" label="{{lastName}}, {{firstName}} ({{username}})" ng-model="criteria.employeeNumber"  />

    //  Setting the value attribute will set the value of NgModel to be the property of the selected object.
    //  <input type="text" class="form-control" my-autocomplete url="/some/url" label="{{lastName}}, {{firstName}} ({{username}})" value="id" ng-model="criteria.employeeNumber"  />

    var directive = {            
        restrict: 'A',
        require: 'ngModel',
        compile: compile
    };

    return directive;

    function compile(elem, attrs) {
        var modelAccessor = $parse(attrs.ngModel),
            labelExpression = attrs.label;

        return function (scope, element, attrs) {
            var
                mappedItems = null,
                allowCustomEntry = attrs.allowCustomEntry || false;

            element.autocomplete({
                source: function (request, response) {
                    $http({
                        url: attrs.url,
                        method: 'GET',
                        params: { term: request.term }
                    })
                    .success(function (data) {
                        mappedItems = $.map(data, function (item) {
                            var result = {};

                            if (typeof item === 'string') {
                                result.label = item;
                                result.value = item;

                                return result;
                            }

                            result.label = $interpolate(labelExpression)(item);

                            if (attrs.value) {
                                result.value = item[attrs.value];
                            }
                            else {
                                result.value = item;
                            }

                            return result;
                        });

                        return response(mappedItems);
                    });
                },

                select: function (event, ui) {
                    scope.$apply(function (scope) {
                        modelAccessor.assign(scope, ui.item.value);
                    });

                    if (attrs.onSelect) {
                        scope.$apply(attrs.onSelect);
                    }

                    element.val(ui.item.label);

                    event.preventDefault();
                },

                change: function () {
                    var
                        currentValue = element.val(),
                        matchingItem = null;

                    if (allowCustomEntry) {
                        return;
                    }

                    if (mappedItems) {
                        for (var i = 0; i < mappedItems.length; i++) {
                            if (mappedItems[i].label === currentValue) {
                                matchingItem = mappedItems[i].label;
                                break;
                            }
                        }
                    }

                    if (!matchingItem) {
                        scope.$apply(function (scope) {
                            modelAccessor.assign(scope, null);
                        });
                    }
                }
            });
        };
    }
}
})();