angular - How to access the nativeElement of a Component in Angular4?

Question

I have two components and one with attribute selector. The child component is,

import { Component, OnInit, Input, ElementRef } from '@angular/core';


@Component({
    selector: '[app-bar-chart]',
    templateUrl: './bar-chart.component.html',
    styleUrls: ['./bar-chart.component.css']
})
export class BarChartComponent implements OnInit {

    @Input() chartContainer: ElementRef;
    @Input() title: string;
    @Input() chartData: {
        title: string,
        content: {
            label: string,
            value: number,
            fill?: string
        }[]
    }[];

    constructor() { }

    ngOnInit() {
        console.log(this.chartContainer);
        console.log(this.chartContainer.nativeElement);
    }

}

The parent component is,

import { Component, OnInit, Output, ViewChild, ElementRef } from '@angular/core';

@Component({
    selector: 'app-dashboard',
    template: `<div><div class="graph-image" style="width: 100%; height: 400px;" app-bar-chart [title]="barChartTitle" [chartData]="ChartData" [chartContainer]="chartContainer" #chartContainer></div></div>`,
    styleUrls: ['./dashboard.component.css']
})
export class DashboardComponent implements OnInit {
    barChartTitle = 'Transaction History';
    ChartData = [
        {
            "title": "May2017",
            "content": [
                {
                    "label": "payable",
                    "value": 10
                }
            ]
        },
        {
            "title": "Jun2017",
            "content": [
                {
                    "label": "payable",
                    "value": 120
                }
            ]
        }
    ];
    constructor() { }

    ngOnInit() {
    }

}

I am passing the local reference from the parent component to the child component. When I am consoling the native element of this local reference it is 'undefined'. How can I access the native element so that I can access the style width and height of the component div.

question from:https://stackoverflow.com/questions/45343810/how-to-access-the-nativeelement-of-a-component-in-angular4

Answer 1

The problem is that if you define a template reference on the element that Angular views as a host element of the component, you will get a reference to the component instance. Here:

<... chartContainer]="chartContainer" #chartContainer></div>

chartContainer will point to the instance of the BarChartComponent and that is why nativeElement is undefined.

To get elementRef of the host element, you don't need any bindings or lifecycle hooks, just inject the element into the constructor:

export class BarChartComponent implements OnInit {
   constructor(element: ElementRef) {
        console.log(element.nativeElement);
   }