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:
A simple Java-like logic that I could think of which might not look very compact in terms of typescript, is as below:
transform(value:IBook[], keyword:string) {
if(!keyword)
return value;
let filteredValues:any=[];
for(let i=0;i<value.length;i++){
if(value[i].name.toLowerCase().includes(keyword.toLowerCase())){
filteredValues.push(value[i]);
}
}
return filteredValues;
}<h2>Available Books</h2>
<input type="text" [(ngModel)]="bookName"/>
<ul class="books">
<li *ngFor="let book of books | search:bookName"
[class.selected]="book === selectedBook"
(click)="onSelect(book)">
<span class="badge">{{book.name}}</span>
</li>
</ul>回答5:
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..
来源：https://stackoverflow.com/questions/46780843/angular-4-filter-search-custom-pipe