Angular 2 filter/search list

Question

I\'m looking for the angular 2 way to do this.

I simply have a list of items, and I want to make an input whos job is to filter the list.

Answer 1

In angular 2 we don't have pre-defined filter and order by as it was with AngularJs, we need to create it for our requirements. It is time killing but we need to do it, (see No FilterPipe or OrderByPipe). In this article we are going to see how we can create filter called pipe in angular 2 and sorting feature called Order By. Let's use a simple dummy json data array for it. Here is the json we will use for our example

First we will see how to use the pipe (filter) by using the search feature:

Create a component with name category.component.ts

    import { Component, OnInit } from '@angular/core';
    @Component({
      selector: 'app-category',
      templateUrl: './category.component.html'
    })
    export class CategoryComponent implements OnInit {

      records: Array;
      isDesc: boolean = false;
      column: string = 'CategoryName';
      constructor() { }

      ngOnInit() {
        this.records= [
          { CategoryID: 1,  CategoryName: "Beverages", Description: "Coffees, teas" },
          { CategoryID: 2,  CategoryName: "Condiments", Description: "Sweet and savory sauces" },
          { CategoryID: 3,  CategoryName: "Confections", Description: "Desserts and candies" },
          { CategoryID: 4,  CategoryName: "Cheeses",  Description: "Smetana, Quark and Cheddar Cheese" },
          { CategoryID: 5,  CategoryName: "Grains/Cereals", Description: "Breads, crackers, pasta, and cereal" },
          { CategoryID: 6,  CategoryName: "Beverages", Description: "Beers, and ales" },
          { CategoryID: 7,  CategoryName: "Condiments", Description: "Selishes, spreads, and seasonings" },
          { CategoryID: 8,  CategoryName: "Confections", Description: "Sweet breads" },
          { CategoryID: 9,  CategoryName: "Cheeses",  Description: "Cheese Burger" },
          { CategoryID: 10, CategoryName: "Grains/Cereals", Description: "Breads, crackers, pasta, and cereal" }
         ];
         // this.sort(this.column);
      }
    }

  

    

      
Category ID
      
Category
      
Description
    
    

      
{{item.CategoryID}}
      
{{item.CategoryName}}
      
{{item.Description}}
    
  

2.Nothing special in this code just initialize our records variable with a list of categories, two other variables isDesc and column are declared which we will use for sorting latter. At the end added this.sort(this.column); latter we will use, once we will have this method.

Note templateUrl: './category.component.html', which we will create next to show the records in tabluar format.

For this create a HTML page called category.component.html, whith following code:

3.Here we use ngFor to repeat the records and show row by row, try to run it and we can see all records in a table.

Search - Filter Records

Say we want to search the table by category name, for this let's add one text box to type and search

5.Now we need to create a pipe to search the result by category because filter is not available as it was in angularjs any more.

Create a file category.pipe.ts and add following code in it.

    import { Pipe, PipeTransform } from '@angular/core';
    @Pipe({ name: 'category' })
    export class CategoryPipe implements PipeTransform {
      transform(categories: any, searchText: any): any {
        if(searchText == null) return categories;

        return categories.filter(function(category){
          return category.CategoryName.toLowerCase().indexOf(searchText.toLowerCase()) > -1;
        })
      }
    }

6.Here in transform method we are accepting the list of categories and search text to search/filter record on the list. Import this file into our category.component.ts file, we want to use it here, as follows:

import { CategoryPipe } from './category.pipe';
@Component({      
  selector: 'app-category',
  templateUrl: './category.component.html',
  pipes: [CategoryPipe]   // This Line       
})

7.Our ngFor loop now need to have our Pipe to filter the records so change it to this.You can see the output in image below

enter image description here