Arranging a group of objects in Angular2

Question

Arranging a group of objects in Angular2

I am facing challenges with organizing an array of objects in Angular2.

The structure of the object is as follows:

[
  {
    "name": "t10",
    "ts": 1476778297100,
    "value": "32.339264",
    "xid": "DP_049908"
  },
  {
    "name": "t17",
    "ts": 1476778341100,
    "value": "true",
    "xid": "DP_693259"
  },
  {
    "name": "t16",
    "ts": 1476778341100,
    "value": "true",
    "xid": "DP_891890"
  }
]

The objects are stored in the values variable.

I simply want to use the *ngFor loop to sort them based on the name property.

<table *ngIf="values.length">
    <tr *ngFor="let elem of values">
      <td>{{ elem.name }}</td>
      <td>{{ elem.ts }}</td>
      <td>{{ elem.value }}</td>
    </tr>
</table>

I attempted to achieve this using pipes, but without success. Any assistance would be greatly appreciated.

Plunker link: https://plnkr.co/edit/e9laTBnqJKb8VzhHEBmn?p=preview

Edit

Here is my pipe:

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

@Component({
  selector: 'watchlist',
  templateUrl: './watchlist.component.html',
  styleUrls: ['./watchlist.component.css'],
  pipes: [ ArraySortPipe ]
})
@Pipe({
  name: "sort"
})

export class ArraySortPipe implements PipeTransform {
  transform(array: Array<string>, args: string): Array<string> {
    array.sort((a: any, b: any) => {
      if (a < b) {
        return -1;
      } else if (a > b) {
        return 1;
      } else {
        return 0;
      }
    });
    return array;
  }
}

Simply add the pipe name to the html file:

<tr *ngFor="let elem of values | sort">

javascript arrays sorting angular typescript

Answer 1

Answer №1

When faced with this dilemma, consider the practicality of using a pipe to solve the problem. Ask yourself if the re-usability of a pipe will truly benefit your project. Will there be a frequent need to sort objects by the "name" key in other arrays or components down the line? Is the data likely to change frequently in a way that complicates simple sorting within the component? Will the array require sorting every time there is a change in the view or inputs?

In my updated example on Plunker, I have implemented sorting within the component's constructor. However, it is possible to extract this functionality into a separate method like sortValuesArray for future re-use.

constructor() {
  this.values.sort((a, b) => {
    if (a.name < b.name) return -1;
    else if (a.name > b.name) return 1;
    else return 0;
  });
}

Updated Plunker

Answer 2

When faced with this dilemma, consider the practicality of using a pipe to solve the problem. Ask yourself if the re-usability of a pipe will truly benefit your project. Will there be a frequent need to sort objects by the "name" key in other arrays or components down the line? Is the data likely to change frequently in a way that complicates simple sorting within the component? Will the array require sorting every time there is a change in the view or inputs?

In my updated example on Plunker, I have implemented sorting within the component's constructor. However, it is possible to extract this functionality into a separate method like sortValuesArray for future re-use.

constructor() {
  this.values.sort((a, b) => {
    if (a.name < b.name) return -1;
    else if (a.name > b.name) return 1;
    else return 0;
  });
}

Updated Plunker

Answer 3

Answer №2

Give this a try:

Organize from A to Z:

this.products.sort((x,y)=>x.ProductName.localeCompare(y.ProductName));

Z to A (in reverse):

this.products.sort((x,y)=>y.ProductName.localeCompare(x.ProductName));

Answer 4

Give this a try:

Organize from A to Z:

this.products.sort((x,y)=>x.ProductName.localeCompare(y.ProductName));

Z to A (in reverse):

this.products.sort((x,y)=>y.ProductName.localeCompare(x.ProductName));

Answer 5

Answer №3

Your current pipe is set up to handle strings, but it's encountering objects instead. You'll need to make some adjustments to accommodate this:

export class SortArrayPipe implements PipeTransform {
  transform(array: Array<any>): Array<string> {
    array.sort((a: any, b: any) => {
      if (a.name < b.name) {
        return -1;
      } else if (a.name > b.name) {
        return 1;
      } else {
        return 0;
      }
    });
    return array;
  }
}

Answer 6

Your current pipe is set up to handle strings, but it's encountering objects instead. You'll need to make some adjustments to accommodate this:

export class SortArrayPipe implements PipeTransform {
  transform(array: Array<any>): Array<string> {
    array.sort((a: any, b: any) => {
      if (a.name < b.name) {
        return -1;
      } else if (a.name > b.name) {
        return 1;
      } else {
        return 0;
      }
    });
    return array;
  }
}

Answer 7

Answer №4

In Angular, it is recommended not to rely on pipes for sorting and filtering, just like in AngularJs.

Using pipes for these tasks can potentially slow down your application and lead to performance issues. Instead, it is advisable to handle sorting within your component before passing it to the template.

You can find more information on this topic at https://angular.io/guide/pipes#no-filter-pipe

If you organize your component layout effectively, you can even implement sorting logic within the setter method:

 @Input()
  set users(users: Array<User>) {
    this.usersResult = (users || []).sort((a: User, b: User) => a.name < b.name ? -1 : 1)
  }

Answer 8

In Angular, it is recommended not to rely on pipes for sorting and filtering, just like in AngularJs.

Using pipes for these tasks can potentially slow down your application and lead to performance issues. Instead, it is advisable to handle sorting within your component before passing it to the template.

You can find more information on this topic at https://angular.io/guide/pipes#no-filter-pipe

If you organize your component layout effectively, you can even implement sorting logic within the setter method:

 @Input()
  set users(users: Array<User>) {
    this.usersResult = (users || []).sort((a: User, b: User) => a.name < b.name ? -1 : 1)
  }

Answer 9

Answer №5

This solution is versatile and can be applied to any similar scenario.

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

@Pipe({
  name: 'sortBy'
})
export class SortByPipe implements PipeTransform {
  transform(arr: Array<any>, prop: any, reverse: boolean = false): any {
    if (arr === undefined) return
    const m = reverse ? -1 : 1
    return arr.sort((a: any, b: any): number => {
      const x = a[prop]
      const y = b[prop]
      return (x === y) ? 0 : (x < y) ? -1*m : 1*m
    })
  }
}

Example of Usage:-

<div *ngFor="let item of list | sortBy: 'isDir': true">

IMPORTANT UPDATE
Please see Bo's answer for information on why filtering and sorting in pipes may not be recommended.

Answer 10

This solution is versatile and can be applied to any similar scenario.

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

@Pipe({
  name: 'sortBy'
})
export class SortByPipe implements PipeTransform {
  transform(arr: Array<any>, prop: any, reverse: boolean = false): any {
    if (arr === undefined) return
    const m = reverse ? -1 : 1
    return arr.sort((a: any, b: any): number => {
      const x = a[prop]
      const y = b[prop]
      return (x === y) ? 0 : (x < y) ? -1*m : 1*m
    })
  }
}

Example of Usage:-

<div *ngFor="let item of list | sortBy: 'isDir': true">

IMPORTANT UPDATE
Please see Bo's answer for information on why filtering and sorting in pipes may not be recommended.

Answer 11

Answer №6

Here's a straightforward example to demonstrate sorting objects in HTML:

 vehicles = ["Dodge", "Fiat", "Audi", "Volvo", "BMW", "Ford"];

If you wish to display the sorted object on the frontend, you can use:

 <li ng-repeat="x in vehicles | orderBy">{{x}}</li>

By default, strings are sorted alphabetically, and numbers are sorted numerically.

Now, consider an array with keys:

customers = [
{"name" : "Bottom-Dollar Marketse" ,"city" : "Tsawassen"},
{"name" : "Alfreds Futterkiste", "city" : "Berlin"},
{"name" : "Bon app", "city" : "Marseille"},
{"name" : "Cactus Comidas para llevar", "city" : "Buenos Aires"},
{"name" : "Bolido Comidas preparadas", "city" : "Madrid"},
{"name" : "Around the Horn", "city" : "London"},
{"name" : "B's Beverages", "city" : "London"}
];

To sort the array by "city" in descending order, you can use:

<li ng-repeat="x in customers | orderBy : '-city'">{{x.name + ", " + x.city}}</li>

If you want to sort the array by "city" in ascending order, use:

<li ng-repeat="x in customers | orderBy : 'city'">{{x.name + ", " + x.city}}</li>

Answer 12

Here's a straightforward example to demonstrate sorting objects in HTML:

 vehicles = ["Dodge", "Fiat", "Audi", "Volvo", "BMW", "Ford"];

If you wish to display the sorted object on the frontend, you can use:

 <li ng-repeat="x in vehicles | orderBy">{{x}}</li>

By default, strings are sorted alphabetically, and numbers are sorted numerically.

Now, consider an array with keys:

customers = [
{"name" : "Bottom-Dollar Marketse" ,"city" : "Tsawassen"},
{"name" : "Alfreds Futterkiste", "city" : "Berlin"},
{"name" : "Bon app", "city" : "Marseille"},
{"name" : "Cactus Comidas para llevar", "city" : "Buenos Aires"},
{"name" : "Bolido Comidas preparadas", "city" : "Madrid"},
{"name" : "Around the Horn", "city" : "London"},
{"name" : "B's Beverages", "city" : "London"}
];

To sort the array by "city" in descending order, you can use:

<li ng-repeat="x in customers | orderBy : '-city'">{{x.name + ", " + x.city}}</li>

If you want to sort the array by "city" in ascending order, use:

<li ng-repeat="x in customers | orderBy : 'city'">{{x.name + ", " + x.city}}</li>

Arranging a group of objects in Angular2

Answer №1

Answer №2

Answer №3

Answer №4

Answer №5

Answer №6

Similar questions

How can I modify the background color of a dimmer in Semantic-UI framework?

React - retrieving the previous page's path after clicking the browser's "back" button

Challenges with importing and using jspdf and autotable-jspdf in Angular 8

Utilizing Angular 2 for Element Selection and Event Handling

Display a component just once in React or React Native by utilizing local storage

JavaScript: Array methods and Functions

The specified userID cannot be located within the array of objects

Constructing a massive numpy array with pytables

Java code producing incorrect output while attempting to retrieve the nth smallest element from an unsorted array

Using Vue.js 3 and Bootstrap 5 to Create a Custom Reusable Modal Component for Programmatically Showing Content

Retrieve the values of a function using the Firebase database

404 error: API endpoint inexistent despite being present

Utilizing JodaTime with JavaScript (AngularJS): A Comprehensive Guide

Tips for accessing a URL page in Ionic 3 without using the ionic-native plugin

Manipulate text with jQuery

Numerous Radio Buttons

How to rotate an object in Threejs using the mouse without having to click and drag?

What could be the reason for this code returning a "module not found" error?

Difficulty commencing a background operation in a node.js application

Guide on using the backbone.js save() method to upload multiple files post-form submission