Struggling to utilize a personalized filter leads to the error message: "Unable to call a function without a designated call signature."

Question

Struggling to utilize a personalized filter leads to the error message: "Unable to call a function without a designated call signature."

Trying to use a custom filter from an Angular controller is resulting in the error message: 'Cannot invoke an expression whose type lacks a call signature'.

I successfully implemented this on my last project, so I'm confused about what could be wrong now.

Currently, the filter doesn't have any logic as I'm focusing on getting it to compile correctly first.

Here is the code for the filter:

/// <reference path="../../typings/reference.ts" />

module app {
'use strict';

/**
 * Filter models
 */
export class ModelFilter {
    public static Factory() {
        return function(input: string) {
            console.log(input);
            return input;
        }
    }
}

angular.module('app')
    .filter('modelFilter', [ModelFilter.Factory]);
}

Below is the section where the filter is being called from the controller:

/// <reference path="../../typings/reference.ts" />

module app {
'use strict';

interface ISearchController {
    vehicles: IVehicles;
    models: any;
    setVehicles(): void;
    updateModels(make: string): void;
}

class SearchController implements ISearchController {

    static $inject = [
        'VehicleMakeService',
        'VehicleModelService',
        '$filter'
    ];
    constructor(private vehicleMakeService: VehicleMakeService,
                private vehicleModelService: VehicleModelService,
                private $filter: ng.IFilterService,
                public vehicles: IVehicles,
                public models: any) {

        this.setVehicles();
    }

    setVehicles(): void {
        this.vehicleMakeService.getVehicles().then((data) => {
            this.vehicles = data;
        });
    }

    updateModels(make: string): void {

        var test = this.$filter('modelFilter')(make); // Error here
    }
}
angular.module('app').controller('SearchController', SearchController);
}

reference.ts:

/// <reference path="./tsd.d.ts" />

//grunt-start
/// <reference path="../app/app.config.ts" />
/// <reference path="../app/app.module.ts" />
/// <reference path="../app/app.route.ts" />
/// <reference path="../app/home/home.controller.ts" />
/// <reference path="../app/home/home.route.ts" />
/// <reference path="../app/models/vehicles.model.ts" />
/// <reference path="../app/results/results.controller.ts" />
/// <reference path="../app/results/results.route.ts" />
/// <reference path="../app/services/cars.service.ts" />
/// <reference path="../app/services/vehicles.make.service.ts" />
/// <reference path="../app/services/vehicles.models.service.ts" />
/// <reference path="../app/templates/search.controller.ts" />
/// <reference path="../app/templates/search.filter.ts" />
//grunt-end

tsd.d.ts:

/// <reference path="angularjs/angular.d.ts" />
/// <reference path="jquery/jquery.d.ts" />
/// <reference path="angular-ui-router/angular-ui-router.d.ts" />
/// <reference path="angularjs/angular-resource.d.ts" />

angularjs typescript angularjs-filter

Answer 1

Answer №1

Here is the updated code snippet:

/// <reference path="typings/angularjs/angular.d.ts" />

module app {

    // UPDATED - Interface for MyModelFilter
    export interface MyModelFilter extends ng.IFilterService {
        (name: 'modelFilter'): (input: string) => string;
    }

    /**
     * Custom filter for models
     */
    export class ModelFilter {
        public static Factory() {
            return function(input: string) {
                console.log(input);
                return input;
            }
        }
    }

    angular.module('app')
        .filter('modelFilter', [ModelFilter.Factory]);
}

module app {

    // Modified SearchController class
    class SearchController {
        constructor(private $filter: MyModelFilter) { 
        }

        updateModels(make: string): void {
            var test = this.$filter('modelFilter')(make);
        }
    }
    angular.module('app').controller('SearchController', SearchController);
}

The issue arises from TypeScript using a specific definition for IFilterService, where <T>(name: string): T; is in play. This results in this.$filter('modelFilter') being recognized as ng.IFilterService instead of your custom ModelFilter.

You can resolve this by introducing a new interface similar to how it's done in the first part of the code.

Your mention of the original code working in another project raises doubts unless modifications were made to the reference.ts file.

Answer 2

Here is the updated code snippet:

/// <reference path="typings/angularjs/angular.d.ts" />

module app {

    // UPDATED - Interface for MyModelFilter
    export interface MyModelFilter extends ng.IFilterService {
        (name: 'modelFilter'): (input: string) => string;
    }

    /**
     * Custom filter for models
     */
    export class ModelFilter {
        public static Factory() {
            return function(input: string) {
                console.log(input);
                return input;
            }
        }
    }

    angular.module('app')
        .filter('modelFilter', [ModelFilter.Factory]);
}

module app {

    // Modified SearchController class
    class SearchController {
        constructor(private $filter: MyModelFilter) { 
        }

        updateModels(make: string): void {
            var test = this.$filter('modelFilter')(make);
        }
    }
    angular.module('app').controller('SearchController', SearchController);
}

The issue arises from TypeScript using a specific definition for IFilterService, where <T>(name: string): T; is in play. This results in this.$filter('modelFilter') being recognized as ng.IFilterService instead of your custom ModelFilter.

You can resolve this by introducing a new interface similar to how it's done in the first part of the code.

Your mention of the original code working in another project raises doubts unless modifications were made to the reference.ts file.

Answer 3

Answer №2

If you take a look at the final line of the IFilterService, you'll notice a generic type specifically for custom filters.

interface IFilterService {
    (name: 'filter'): IFilterFilter;
    (name: 'currency'): IFilterCurrency;
    (name: 'number'): IFilterNumber;
    (name: 'date'): IFilterDate;
    (name: 'json'): IFilterJson;
    (name: 'lowercase'): IFilterLowercase;
    (name: 'uppercase'): IFilterUppercase;
    (name: 'limitTo'): IFilterLimitTo;
    (name: 'orderBy'): IFilterOrderBy;
    /**
     * Usage:
     * $filter(name);
     *
     * @param name Name of the filter function to retrieve
     */
    <T>(name: string): T; 
}

The error message indicates that your custom filter doesn't have a call signature. To address this, you can define an interface for your filter with a call signature:

export interface MyModelFilter {
    (input: string): string;
}

When calling your filter, utilize the IFilterService's generic type to associate your call signature with your custom filter

updateModels(make: string): void {
     var test = this.$filter<MyModelFilter>('modelFilter')(make);
}

Answer 4

If you take a look at the final line of the IFilterService, you'll notice a generic type specifically for custom filters.

interface IFilterService {
    (name: 'filter'): IFilterFilter;
    (name: 'currency'): IFilterCurrency;
    (name: 'number'): IFilterNumber;
    (name: 'date'): IFilterDate;
    (name: 'json'): IFilterJson;
    (name: 'lowercase'): IFilterLowercase;
    (name: 'uppercase'): IFilterUppercase;
    (name: 'limitTo'): IFilterLimitTo;
    (name: 'orderBy'): IFilterOrderBy;
    /**
     * Usage:
     * $filter(name);
     *
     * @param name Name of the filter function to retrieve
     */
    <T>(name: string): T; 
}

The error message indicates that your custom filter doesn't have a call signature. To address this, you can define an interface for your filter with a call signature:

export interface MyModelFilter {
    (input: string): string;
}

When calling your filter, utilize the IFilterService's generic type to associate your call signature with your custom filter

updateModels(make: string): void {
     var test = this.$filter<MyModelFilter>('modelFilter')(make);
}

Answer 5

Answer №3

Allow me to provide a similar example showcasing how the Moment library can be utilized for date formatting, whether in a controller or on the front end.

export interface IMomentFilter extends ng.IFilterService {
    (name: 'momentFilter'): (dateString: string, format: string) => string;
}

export class MomentFilter {
    public static Factory() {
        return function (dateString: string, format: string) {
            return moment(dateString).format(format);
        }
    }
}

Here is an example of how it can be implemented in the controller to format a date using the ag-grid cellRenderer:

var columnDefs = [
{
    headerName: "Reported Date", 
    field: "reportedDate", 
    cellRenderer: function (params) 
    {
        return $filter('momentFilter')(params.value, "MM/DD/YYYY");
    }
}];

And here is an example of how it can be used on the front end:

<div class="col-xs-6 col-sm-6 col-md-6 col-lg-6">Created Date:
    <label class="field">
    <label class="field">{{vm.model.reportedDate| momentFilter:'MM/DD/YYYY' }}</label>
    </label>
</div>

I trust this explanation serves you well. Many thanks for sharing the original post. I was struggling to grasp the correct syntax while utilizing the IFilterService interface.

Answer 6

Allow me to provide a similar example showcasing how the Moment library can be utilized for date formatting, whether in a controller or on the front end.

export interface IMomentFilter extends ng.IFilterService {
    (name: 'momentFilter'): (dateString: string, format: string) => string;
}

export class MomentFilter {
    public static Factory() {
        return function (dateString: string, format: string) {
            return moment(dateString).format(format);
        }
    }
}

Here is an example of how it can be implemented in the controller to format a date using the ag-grid cellRenderer:

var columnDefs = [
{
    headerName: "Reported Date", 
    field: "reportedDate", 
    cellRenderer: function (params) 
    {
        return $filter('momentFilter')(params.value, "MM/DD/YYYY");
    }
}];

And here is an example of how it can be used on the front end:

<div class="col-xs-6 col-sm-6 col-md-6 col-lg-6">Created Date:
    <label class="field">
    <label class="field">{{vm.model.reportedDate| momentFilter:'MM/DD/YYYY' }}</label>
    </label>
</div>

I trust this explanation serves you well. Many thanks for sharing the original post. I was struggling to grasp the correct syntax while utilizing the IFilterService interface.

Struggling to utilize a personalized filter leads to the error message: "Unable to call a function without a designated call signature."

Answer №1

Answer №2

Answer №3

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