BarChartComponent-1.ts

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

import { d3 } from 'd3';

@Component({
  selector: 'bar-chart',
  template: `<svg [attr.width]="width" [attr.height]="height"></svg>`
})
export class BarChartComponent {
  @Input() frequencies: {[key:string]:number;};
  width: number;
  height: number;

  constructor() {
    // let's keep size constant
    this.width = 480;
    this.height = 480;
  }

  // ...
}