Angular 4 Filter Search Custom Pipe

问题:

So I am trying to build a custom pipe to do a search filter of multiple values in a ngFor loop. I have looked for a number of hours for a good working example, and most of them are based on previous builds and don't seem to work. So I was building the Pipe and using the console to give me the values. However, I cannot seem to get the input text to show up.

Here are the previous places I have looked to find working examples:

Angular 4 Pipe Filter

http://jilles.me/ng-filter-in-angular2-pipes/

https://mytechnetknowhows.wordpress.com/2017/02/18/angular-2-pipes-passing-multiple-filters-to-pipes/

https://plnkr.co/edit/vRvnNUULmBpkbLUYk4uw?p=preview

https://www.youtube.com/results?search_query=filter+search+angular+2

https://www.youtube.com/watch?v=UgMhQpkjCFg

Here is the code that I currently have:

component.html

<input type="text" class="form-control" placeholder="Search" ngModel="query" id="listSearch" #LockFilter>

      <div class="panel panel-default col-xs-12 col-sm-11" *ngFor="let lock of locked | LockFilter: query">
        <input type="checkbox" ngModel="lock.checked" (change)="openModal($event, lock)" class="check" id="{{lock.ID}}">
        <label for="{{lock.ID}}" class="check-label"></label>
        <h3 class="card-text name" ngModel="lock.name">{{lock.User}}</h3>
        <h3 class="card-text auth" ngModel="lock.auth">{{lock.AuthID}}</h3>
        <h3 class="card-text form" ngModel="lock.form">{{lock.FormName}}</h3>
        <h3 class="card-text win" ngModel="lock.win">{{lock.WinHandle}}</h3>
      </div>

pipe.ts

import { Pipe, PipeTransform } from '@angular/core';

@Pipe({
  name: 'LockFilter'
})

export class LockFilterPipe implements PipeTransform {
  transform(locked: any, query: string): any {
    console.log(locked); //this shows in the console
    console.log(query); //this does not show anything in the console when typing
    if(!query) {
      return locked;
    }
    return locked.filter((lock) => {
      return lock.User.toLowerCase().match(query.toLowerCase());
    });
  }
}

I have imported the pipe into the module.

I am still a little newer to Angular 4 and am trying to figure out how to make this work. Anyways thanks for your help!

I guess I will need to be more specific. I already built out a filter search in JS that does not filter all of the options, which is what I am trying to do. Not just filter the User Name. I am filtering all 4 pieces of data. I chose a Pipe as this was what Angular suggests you do as they originally used them in AngularJS. I am just trying to essentially recreate the filter pipe we had in AngularJS that they removed for performance. All options I have found don't work, or are from previous builds of Angular.

If you need anything else from my code let me know.

回答1:

I have to implement search functionality in my local and Here is Updated your code. please do this way.

Here is the code that I have to update.

directory Structure

app/
   _pipe/
        search/
          search.pipe.ts
          search.pipe.spec.ts
app/ 
   app.component.css
   app.component.html
   app.component.ts
   app.module.ts
   app.component.spec.ts

command run for creating pipe

ng g pipe search

component.html

<input type="text" class="form-control" placeholder="Search" [(ngModel)]="query" id="listSearch">
    <div class="panel panel-default col-xs-12 col-sm-11" *ngFor="let lock of locked | LockFilter: query">
    <input type="checkbox" (change)="openModal($event, lock)" class="check" id="{{lock.ID}}">
    <label [for]="lock.ID" class="check-label"></label>
    <h3 class="card-text name">{{lock.User}}</h3>
    <h3 class="card-text auth">{{lock.AuthID}}</h3>
    <h3 class="card-text form">{{lock.FormName}}</h3>
    <h3 class="card-text win">{{lock.WinHandle}}</h3>
</div>

component.js

Note: In this file, i have to use dummy records for implementation and testing purpose.

import { Component, OnInit } from '@angular/core';
import { FormsModule }   from '@angular/forms';

@Component({
    selector: 'app-root',
    templateUrl: './app.component.html',
    styleUrls: ['./app.component.css']
})
    export class AppComponent implements OnInit{
    public search:any = '';
    locked: any[] = [];

    constructor(){}

    ngOnInit(){
        this.locked = [
            {ID: 1, User: 'Agustin', AuthID: '68114', FormName: 'Fellman', WinHandle: 'Oak Way'},
            {ID: 2, User: 'Alden', AuthID: '98101', FormName: 'Raccoon Run', WinHandle: 'Newsome'},
            {ID: 3, User: 'Ramon', AuthID: '28586', FormName: 'Yorkshire Circle', WinHandle: 'Dennis'},
            {ID: 4, User: 'Elbert', AuthID: '91775', FormName: 'Lee', WinHandle: 'Middleville Road'},
        ]
    }
}

module.ts

import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { FormsModule }   from '@angular/forms';
import { AppComponent } from './app.component';
import { SearchPipe } from './_pipe/search/search.pipe';


@NgModule({
  declarations: [
    AppComponent,
    SearchPipe
  ],
  imports: [
    BrowserModule,
    FormsModule
  ],
  providers: [],
  bootstrap: [AppComponent]
})
export class AppModule { }

pipe.ts

import { Pipe, PipeTransform } from '@angular/core';

@Pipe({
    name: 'LockFilter'
})

export class SearchPipe implements PipeTransform {
    transform(value: any, args?: any): any {

        if(!value)return null;
        if(!args)return value;

        args = args.toLowerCase();

        return value.filter(function(item){
            return JSON.stringify(item).toLowerCase().includes(args);
        });
    }
}

I hope you are getting the pipe functionality and this will help you.

回答2:

Simple filterPipe for Angular 2+

import { Pipe, PipeTransform } from '@angular/core';

@Pipe({
  name: 'filter'
})
export class filterPipe implements PipeTransform {

  transform(items: any[], field:string, value: string): any[] {

    if(!items) return [];
    if(!value) return items;


    return items.filter( str => {
          return str[field].toLowerCase().includes(value.toLowerCase());
        });
   }
}

Here is the HTML

<input type="text" class="form-control" placeholder="Search" id="listSearch" #search>
    <div class="panel panel-default col-xs-12 col-sm-11" *ngFor="let lock of locked | filter:'propName': search.value>
    <input type="checkbox" (change)="openModal($event, lock)" class="check" id="{{lock.ID}}">
    <label [for]="lock.ID" class="check-label"></label>
    <h3 class="card-text name">{{lock.User}}</h3>
    <h3 class="card-text auth">{{lock.AuthID}}</h3>
    <h3 class="card-text form">{{lock.FormName}}</h3>
    <h3 class="card-text win">{{lock.WinHandle}}</h3>
</div>

in HTML PropName is dummy text. In place of PropName use your any object property key.

回答3:

Here is simple explanation to create custom pipe..as available pipes does not support it. I found this solution here..Nicely explained it

Create pipe file advanced-filter.pipe

import {Pipe, PipeTransform} from '@angular/core';

@Pipe({
  name: 'advancedFilters'
})

export class AdvancedFilterPipe implements PipeTransform {

  transform(array: any[], ...args): any {
    if (array == null) {
      return null;
    }

    return array.filter(function(obj) {
      if (args[1]) {
        return obj.status === args[0];
      }
      return array;
    });

  }

}

Here, array – will be data array passed to your custom pipe obj – will be the object of data by using that object you can add condition to filter data

We have added condition obj.status === args[0] so that data will get filter on status which is passed in .html file

Now, import and declare custom pipe in module.ts file of component:

import {AdvancedFilterPipe} from './basic-filter.pipe';

//Declare pipe

@NgModule({

    imports: [DataTableModule, HttpModule, CommonModule, FormsModule, ChartModule, RouterModule],

    declarations: [ DashboardComponent, AdvancedFilterPipe],

    exports: [ DashboardComponent ],

    providers: [{provide: HighchartsStatic}]

})

Use of created custom angular pipe in .html file

<table class="table table-bordered" [mfData]="data | advancedFilters: status" #mf="mfDataTable" [mfRowsOnPage]="rowsOnPage" [(mfSortBy)]="sortBy" [(mfSortOrder)]="sortOrder">

                <thead>
                       <tr>
                             <th class="sortable-column" width="12%">
                                 <mfDefaultSorter by="inquiry_originator">Origin</mfDefaultSorter>
                             </th>
                        </tr>
                </thead>

                <tbody class="dashboard-grid">

                                <ng-container *ngFor="let item of mf.data; let counter = index;">

                                                <tr class="data-row {{ item.status }} grid-panel-class-{{ counter }}">                                      

                                                                <td class="align-center">{{ item.trn_date }}</td>

                                                                <td>{{ item.trn_ref }}</td>

                                                </tr>

                </tbody>

</table>


//If you are using *ngFor and want to use custom angular pipe then below is code

<li *ngFor="let num of (numbers | advancedFilters: status">
  {{ num | ordinal }}
</li>

回答4:

You can use the given function instead on the (input) event of your input box

filterNames(event)
{
 this.names_list = this.names_list.filter(function(tag) {
 return tag.name.toLowerCase().indexOf(event.target.value.toLowerCase()) >= 0;
 });
}

Hope it helps..