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Angular PrimeNG TreeTable Lazy Loading

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Angular PrimeNG is an open-source framework with a rich set of native Angular UI components that are used for great styling and this framework is used to make responsive websites with very much ease. This article will show us how to use TreeTable Lazy Loading in Angular PrimeNG.

Angular PrimeNG TreeTable Lazy Loading is used to lazy load the data of the TreeTable component. It loads the data when required and makes the TreeTable more interactive and user-friendly.

Syntax:

// In app.component.html
<p-treeTable
  [columns]="cols"
  [value]="tableData"
  [lazy]="true"
  (onLazyLoad)="loadNodes($event)"
  [loading]="loading">
  ...
</p-treeTable>

// In app.component.ts 
loadNodes(event) {
    // lazy function
}

 

Creating Angular application & Module Installation:

Step 1: Create an Angular application using the following command.

ng new appname

Step 2:  After creating your project folder i.e. appname, move to it using the following command.

cd appname

Step 3: Install PrimeNG in your given directory.

npm install primeng --save
npm install primeicons --save

Project Structure: It will look like the following:

Project Structure

Example 1: Below is a simple example demonstrating the use of the Angular PrimeNG TreeTable Lazy Loading.

app.component.html




<h2 style="color: green">GeeksforGeeks</h2>
<h4>Angular PrimeNG TreeTable Lazy Loading</h4>
  
<p-treeTable 
    [columns]="cols" 
    [value]="tableData" 
    [lazy]="true" 
    (onLazyLoad)="loadNodes($event)" 
    [loading]="loading">
    <ng-template pTemplate="header">
        <tr>
            <th>First Name</th>
            <th>Last Name</th>
            <th>Age</th>
        </tr>
    </ng-template>
  
    <ng-template 
        pTemplate="body" 
        let-rowNode 
        let-rowData="rowData">
        <tr>
            <td>
                <p-treeTableToggler 
                    [rowNode]="rowNode">
                </p-treeTableToggler>
                {{ rowData.firstname }}
            </td>
            <td>{{ rowData.lastname }}</td>
            <td>{{ rowData.age }}</td>
        </tr>
    </ng-template>
</p-treeTable>


app.component.ts




import { Component, OnInit } from '@angular/core';
import { NodeService } from './nodeservice';
import { TreeNode } from 'primeng/api';
  
@Component({
    selector: 'app-root',
    templateUrl: './app.component.html'
})
export class AppComponent {
    tableData: TreeNode[] = [];
    cols: any[] = [];
    loading: boolean = false;
    constructor(private nodeService: NodeService) { }
  
    ngOnInit() {
        this.cols = [
            { field: 'firstname', header: 'First Name' },
            { field: 'lastname', header: 'Last Name' },
  
            { field: 'age', header: 'Age' },
        ];
        this.loading = true;
  
    }
    loadNodes(event: any) {
        this.loading = true;
        setTimeout(() => {
            this.tableData = [
                {
                    data: {
                        firstname: 'David',
                        lastname: 'ace',
                        age: '40',
                    },
                    children: [
                        {
                            data: {
                                firstname: 'Nathan',
                                lastname: 'ace',
  
                                age: '16',
                            },
                            children: [
                                {
                                    data: {
                                        firstname: 'Abe',
                                        lastname: 'ace',
  
                                        age: '12',
                                    },
                                },
                                {
                                    data: {
                                        firstname: 'Ksi',
                                        lastname: 'ace',
  
                                        age: '12',
                                    },
                                },
                            ],
                        },
                        {
                            data: {
                                firstname: 'Shane',
                                lastname: 'ace',
  
                                age: '14',
                            },
                        },
                    ],
                },
                {
                    data: {
                        firstname: 'Warner',
                        lastname: 'ace',
  
                        age: '55',
                    },
                    children: [
                        {
                            data: {
                                lastname: 'ace',
                                firstname: 'Michelle',
                                age: '20',
                            },
                        },
                        {
                            data: {
                                firstname: 'Charlie',
                                lastname: 'ace',
  
                                age: '24',
                            },
                        },
                    ],
                },
                {
                    data: {
                        firstname: 'Max',
                        lastname: 'ace',
  
                        age: '55',
                    },
                    children: [
                        {
                            data: {
                                firstname: 'Michelle',
                                lastname: 'ace',
  
                                age: '20',
                            },
                        },
                        {
                            data: {
                                firstname: 'Charlie',
                                lastname: 'ace',
  
                                age: '24',
                            },
                        },
                    ],
                },
                {
                    data: {
                        firstname: 'Willy',
                        lastname: 'ace',
  
                        age: '55',
                    },
                    children: [
                        {
                            data: {
                                firstname: 'Michelle',
                                lastname: 'ace',
  
                                age: '20',
                            },
                        },
                        {
                            data: {
                                firstname: 'Charlie',
                                lastname: 'ace',
  
                                age: '24',
                            },
                        },
                    ],
                },
                {
                    data: {
                        firstname: 'Miley',
                        lastname: 'ace',
  
                        age: '55',
                    },
                    children: [
                        {
                            data: {
                                firstname: 'Michelle',
                                lastname: 'ace',
  
                                age: '20',
                            },
                        },
                        {
                            data: {
                                firstname: 'Charlie',
                                lastname: 'ace',
  
                                age: '24',
                            },
                        },
                    ],
                },
                {
                    data: {
                        firstname: 'Sam',
                        lastname: 'ace',
  
                        age: '55',
                    },
                    children: [
                        {
                            data: {
                                firstname: 'Michelle',
                                lastname: 'ace',
  
                                age: '20',
                            },
                        },
                        {
                            data: {
                                firstname: 'Charlie',
                                lastname: 'ace',
  
                                age: '24',
                            },
                        },
                    ],
                },
                {
                    data: {
                        firstname: 'James',
                        lastname: 'ace',
  
                        age: '55',
                    },
                    children: [
                        {
                            data: {
                                firstname: 'Michelle',
                                lastname: 'ace',
  
                                age: '20',
                            },
                        },
                        {
                            data: {
                                lastname: 'ace',
                                firstname: 'Charlie',
  
                                age: '24',
                            },
                        },
                    ],
                },
            ];
            this.loading = false;
        }, 1000);
  
    }
}


app.module.ts




import { NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { FormsModule } from '@angular/forms';
import { HttpClientModule } from '@angular/common/http';
import { BrowserAnimationsModule }
    from '@angular/platform-browser/animations';
import { AppComponent } from './app.component';
import { NodeService } from './nodeservice';
import { TreeTableModule } from 'primeng/treetable';
import { ButtonModule } from 'primeng/button';
import { InputTextModule } from 'primeng/inputtext';
  
@NgModule({
    imports: [
        BrowserModule,
        BrowserAnimationsModule,
        TreeTableModule,
        ButtonModule,
        InputTextModule,
        HttpClientModule,
        FormsModule,
    ],
    declarations: [AppComponent],
    bootstrap: [AppComponent],
    providers: [NodeService],
})
  
export class AppModule { }


Output:

 

Example 2: Below is another example demonstrating the use of the Angular PrimeNG TreeTable Lazy Loading. In this example, we are lazy loading the data for 5 seconds.

app.component.ts

app.component.html




<h2 style="color: green">GeeksforGeeks</h2>
<h4>Angular PrimeNG TreeTable Lazy Loading</h4>
  
<p-treeTable 
    [columns]="cols" 
    [value]="tableData" 
    [lazy]="true" 
    (onLazyLoad)="loadNodes($event)" 
    [loading]="loading">
    <ng-template pTemplate="header">
        <tr>
            <th>First Name</th>
            <th>Last Name</th>
            <th>Age</th>
        </tr>
    </ng-template>
  
    <ng-template 
        pTemplate="body" 
        let-rowNode 
        let-rowData="rowData">
        <tr>
            <td>
                <p-treeTableToggler 
                    [rowNode]="rowNode">
                </p-treeTableToggler>
                {{ rowData.firstname }}
            </td>
            <td>{{ rowData.lastname }}</td>
            <td>{{ rowData.age }}</td>
        </tr>
    </ng-template>
</p-treeTable>


app.component.ts




import { Component, OnInit } from '@angular/core';
import { NodeService } from './nodeservice';
import { TreeNode } from 'primeng/api';
  
@Component({
    selector: 'app-root',
    templateUrl: './app.component.html',
})
export class AppComponent {
    tableData: TreeNode[] = [];
    cols: any[] = [];
    loading: boolean = false;
    constructor(private nodeService: NodeService) { }
  
    ngOnInit() {
        this.cols = [
            { field: 'firstname', header: 'First Name' },
            { field: 'lastname', header: 'Last Name' },
  
            { field: 'age', header: 'Age' },
        ];
        this.loading = true;
    }
    loadNodes(event: any) {
        this.loading = true;
        setTimeout(() => {
            this.tableData = [
                {
                    data: {
                        firstname: 'David',
                        lastname: 'ace',
                        age: '40',
                    },
                    children: [
                        {
                            data: {
                                firstname: 'Nathan',
                                lastname: 'ace',
  
                                age: '16',
                            },
                            children: [
                                {
                                    data: {
                                        firstname: 'Abe',
                                        lastname: 'ace',
  
                                        age: '12',
                                    },
                                },
                                {
                                    data: {
                                        firstname: 'Ksi',
                                        lastname: 'ace',
  
                                        age: '12',
                                    },
                                },
                            ],
                        },
                        {
                            data: {
                                firstname: 'Shane',
                                lastname: 'ace',
  
                                age: '14',
                            },
                        },
                    ],
                },
                {
                    data: {
                        firstname: 'Warner',
                        lastname: 'ace',
  
                        age: '55',
                    },
                    children: [
                        {
                            data: {
                                lastname: 'ace',
                                firstname: 'Michelle',
                                age: '20',
                            },
                        },
                        {
                            data: {
                                firstname: 'Charlie',
                                lastname: 'ace',
  
                                age: '24',
                            },
                        },
                    ],
                },
                {
                    data: {
                        firstname: 'Max',
                        lastname: 'ace',
  
                        age: '55',
                    },
                    children: [
                        {
                            data: {
                                firstname: 'Michelle',
                                lastname: 'ace',
  
                                age: '20',
                            },
                        },
                        {
                            data: {
                                firstname: 'Charlie',
                                lastname: 'ace',
  
                                age: '24',
                            },
                        },
                    ],
                },
                {
                    data: {
                        firstname: 'Willy',
                        lastname: 'ace',
  
                        age: '55',
                    },
                    children: [
                        {
                            data: {
                                firstname: 'Michelle',
                                lastname: 'ace',
  
                                age: '20',
                            },
                        },
                        {
                            data: {
                                firstname: 'Charlie',
                                lastname: 'ace',
  
                                age: '24',
                            },
                        },
                    ],
                },
                {
                    data: {
                        firstname: 'Miley',
                        lastname: 'ace',
  
                        age: '55',
                    },
                    children: [
                        {
                            data: {
                                firstname: 'Michelle',
                                lastname: 'ace',
  
                                age: '20',
                            },
                        },
                        {
                            data: {
                                firstname: 'Charlie',
                                lastname: 'ace',
  
                                age: '24',
                            },
                        },
                    ],
                },
                {
                    data: {
                        firstname: 'Sam',
                        lastname: 'ace',
  
                        age: '55',
                    },
                    children: [
                        {
                            data: {
                                firstname: 'Michelle',
                                lastname: 'ace',
  
                                age: '20',
                            },
                        },
                        {
                            data: {
                                firstname: 'Charlie',
                                lastname: 'ace',
  
                                age: '24',
                            },
                        },
                    ],
                },
                {
                    data: {
                        firstname: 'James',
                        lastname: 'ace',
  
                        age: '55',
                    },
                    children: [
                        {
                            data: {
                                firstname: 'Michelle',
                                lastname: 'ace',
  
                                age: '20',
                            },
                        },
                        {
                            data: {
                                lastname: 'ace',
                                firstname: 'Charlie',
  
                                age: '24',
                            },
                        },
                    ],
                },
            ];
            this.loading = false;
        }, 5000);
    }
}


app.module.ts




import { NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { FormsModule } from '@angular/forms';
import { HttpClientModule } from '@angular/common/http';
import { BrowserAnimationsModule }
    from '@angular/platform-browser/animations';
import { AppComponent } from './app.component';
import { NodeService } from './nodeservice';
import { TreeTableModule } from 'primeng/treetable';
import { ButtonModule } from 'primeng/button';
import { InputTextModule } from 'primeng/inputtext';
  
@NgModule({
    imports: [
        BrowserModule,
        BrowserAnimationsModule,
        TreeTableModule,
        ButtonModule,
        InputTextModule,
        HttpClientModule,
        FormsModule,
    ],
    declarations: [AppComponent],
    bootstrap: [AppComponent],
    providers: [NodeService],
})
  
export class AppModule { }


Output:

 

Reference: https://primefaces.org/primeng/treetable/lazy



Last Updated : 26 Sep, 2022
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