The 'filter' property is not found on the type '{}'

I'm currently attempting to implement a custom filter for an autocomplete input text following the Angular Material guide.

https://material.angular.io/components/autocomplete/overview

Here's what I have so far:

TS

import { Component, OnInit } from '@angular/core';
import { TemplateRef } from '@angular/core';
import { FormControl } from "@angular/forms";
import { Observable } from "rxjs";
import { map, startWith, filter } from 'rxjs/operators';

(...)

export class AppComponent implements OnInit {
  title = 'Your Profile';
  displayedColumns: string[] = ['selected', 'name', 'description', 'pnr'];
  dataSource = ELEMENT_DATA;

  myControl = new FormControl();
  options: any[] = ['One', 'Two', 'Three'];
  filteredOptions: Observable<string[]>;

  ngOnInit() {
     this.filteredOptions = this.myControl.valueChanges
      .pipe(
        startWith(''),
        map(value => this._filter(value))
      );
  }

  private _filter(value: any): string[] {
    const filterValue = value.toLowerCase();

    return this.options.filter(option =>   option.toLowerCase().includes(filterValue));
  }
}

HTML

<mat-form-field class="full-with-field" hintLabel="(or code)"> 
    <input matInput placeholder="RP oficina/Nombre empresa" [formControl]="companyControl" [matAutocomplete]="auto">
    <mat-autocomplete #auto="matAutocomplete"> 
        <mat-option *ngFor="let option of filteredOptions | async" [value]="option">
        {{option}} 
        </mat-option> 
    </mat-autocomplete> 
</mat-form-field>

However, during testing, I encountered an error in the return statement. The specific error message received is:

[ts] Property 'filter' does not exist on type '{}'.

The 'options' variable is clearly part of an array, so it's puzzling why this error is occurring.

Further debugging in Firefox revealed the following error message:

Uncaught Error: Template parse errors:
Can't bind to 'formControl' since it isn't a known property of 'input'. ("="(or code)"> <input
                            matInput placeholder="RP oficina/Nombre empresa"
                            [ERROR ->][formControl]="companyControl" [matAutocomplete]="auto">
                        <mat-autocomplete #auto="matAutocompl"): ng:///AppModule/AppComponent.html@26:7
... (Error details truncated)

Answer №1

Step 1.

ngOnInit() {
     this.filteredOptions = this.myControl.valueChanges
      .pipe(
        startWith(''),
        map(value => this._filter(value))
   );
}
private _filter(value: any): string[] { const filterValue = value.toLowerCase(); 
//Utilize the pipe 
return this.options.pipe(filter(option => option.toLowerCase().includes(filterValue)));
}

Step 2.

To resolve the console error

If you are using formControl, ensure you have imported ReactiveFormsModule Ensure that you have added ReactiveFormsModule to the imports array

import {FormsModule, ReactiveFormsModule} from '@angular/forms';

@NgModule({
 imports: [
   BrowserModule,
   FormsModule,
   ReactiveFormsModule,
   MaterialModule,
],

Check out the documentation here

Answer №2

It appears that you may have overlooked some import statements. For Rxjs version 6, consider using the following:

import { filter } from 'rxjs/operators';

Alternatively, for Rxjs version 5, try this instead:

import 'rxjs/add/operator/filter';

Additionally, I would recommend installing an intellisense tool in your code editor for a smoother development experience.

Answer №3

The missing piece is the absence of the opening [ within matAutocomplete

Similar questions

If you have not found the answer to your question or you are interested in this topic, then look at other similar questions below or use the search

NativeScript element isn't showing up

Being relatively new to application development with NativeScript, I find myself in a situation where I need assistance in finding a solution. Drawing from my experience with PHP, I am now looking to create a template for each "page" of the application. Th ...

Gathering the output from every function within an array of functions

I've searched extensively for a solution to this dilemma, but have had no luck so far. Therefore, I am turning to the community for help. Please feel free to direct me to any existing similar queries. My challenge involves working with an array of fu ...

What is the correct way to include a JSON file in TypeScript?

Currently, I'm attempting to reference a JSON path and save it as a constant. My initial approach involved creating a reference with a string and then sending it back as a response using res.send, which successfully returned the string. However, I am ...

complete() method is not triggered by Observable

Note: I understand that there is a timer observable from rxjs, but for the purpose of this project, I am using it as a proof of concept to enhance my understanding of observables. In my Angular application, I have developed a timer with a start button, a ...

Developing Angular2 applications in Visual Studio Team Services (formerly known as Visual Studio Online)

Currently, I have an angular2 client integrated into a Visual Studio vNext (ASP.Net 5) project. During my attempt to create a build in Visual Studio Team Services, I encountered errors similar to this one during the build step: It appears that module &a ...

VueJS - When using common functions, the reference to "this" may be undefined

I'm struggling to extract a function that can be used across various components. The issue is that when I try to use "this", it is coming up as undefined. I'm not sure of the best practice for handling this situation and how to properly assign th ...

Verify user using Cognito user pool log-in information

Is it possible to authenticate a user using only user pool credentials without an identity pool/IdentityPoolId? Check out this link for more information: https://github.com/aws/amazon-cognito-identity-js The example provided in the link above specifically ...

How to fetch a file from a Spring Boot server using Angular 4

I'm currently developing a Spring Boot server with an Angular 4 front-end. I've created a service that allows users to download a .zip file from the front-end using HttpClient. Below is my code: Angular service: getZip(fileName: string) : Obser ...

Encountering a Problem with vue-check-view Library in Typescript

After successfully declaring the js plugin with *.d.ts, I encountered an issue where my view was blank after using .use(checkView). Does the library vue-check-view support Typescript? Error: Uncaught TypeError: Cannot read property '$isServer' o ...

What is the method by which the Material-UI Button component determines the properties for the component that is passed to the `component` prop

Could someone please clarify how Material-UI enhances the properties of its Button component by incorporating the properties of a specific component if passed in the component attribute? interface MyLinkProps extends ButtonBaseProps { someRandomProp: str ...

Angular Routing: Dynamically loading modules as children within lazy loaded modules

I am working on a complex application where I need to load a module as a child of lazy loaded modules. For instance, I want the URL path to look like this: https://localhost:8080/ui/examplemodule/new The examplemodule and new are separate modules with t ...

Issue with the text wrapping of Angular mat-list-option items

When the text of my checkboxes is too long, it doesn't wrap properly. Please see the image below for reference: Click here to view Checkbox image and check the red box Here is my HTML code: <mat-selection-list #rolesSelection ...

Issue with Jest mock function failing to trigger axios instance function causing it to return undefined

I initially found a solution on this StackOverflow thread However, I wanted to add my own helper function that generates a fresh Axios instance with the user's authentication token. Here is what I came up with: import axios from "axios"; c ...

What is the best way to organize an array both alphabetically and by the length of its elements?

Imagine I am working with an array like this: ['a', 'c', 'bb', 'aaa', 'bbb', 'aa']. My goal is to sort it in the following order: aaa, aa, a, bbb, bb, c. this.array= this.array.sort((n1, n2) => ...

When trying to run "ng s -o/ng s/ng build" commands in Angular Cli, there is an issue where no output is displayed

Running "ng serve", "ng serve -o", and "ng build" does not display any output. I am in need of Angular for my project, so if anyone can offer assistance, please help me. https://i.sstatic.net/SmjaL.jpg ...

Describing a function in Typescript that takes an array of functions as input, and outputs an array containing the return types of each function

Can the code snippet below be accurately typed? function determineElementTypes(...array: Array<(() => string) | (() => number) | (() => {prop: string}) | (() => number[])>) { /// .. do something /// .. and then return an array ...

Error: Unable to locate the type definition file for the '@babel' package

I am currently working on a new project and here is the content of my package.json file. { "name": "dapp-boilerplate", "version": "1.0.0", "main": "index.js", "license": "MI ...

Encountered a type error during project compilation: "Type '(e: ChangeEvent<{ value: string[] | unknown; }>) => void' error occurred."

I recently started working with react and I'm facing an issue with a CustomMultiSelect component in my project. When I try to call events in another component, I encounter the following error during the project build: ERROR: [BUILD] Failed to compile ...

Oops! An issue occurred during the `ng build` command, indicating a ReferenceError with the message "Buffer is not defined

I'm facing an issue while trying to utilize Buffer in my angular component ts for encoding the Authorization string. Even after attempting npm i @types/node and adding "node" to types field in tsconfig.json, it still doesn't compile with ng buil ...

Sending VSCode to external functions

My primary entrypoint containing the activate() function is: extension.ts import * as vscode from "vscode"; import { subscribe } from "./eventListeners.ts"; export function activate(context: vscode.ExtensionContext) { vscode.command ...