ngx-charts realtime line chart component possible solution

line-chart.component.ts

import {
  Component,
  Input,
  Output,
  EventEmitter,
  ViewEncapsulation,
  HostListener,
  ChangeDetectionStrategy,
  ContentChild,
  TemplateRef,
} from '@angular/core';
import {
  trigger,
  style,
  animate,
  transition
} from '@angular/animations';
import { scaleLinear, scaleTime, scalePoint } from 'd3-scale';
import { curveLinear } from 'd3-shape';

import { LineChartComponent as BaseLineChartComponent} from '@swimlane/ngx-charts/release/line-chart/line-chart.component';
import { calculateViewDimensions, ViewDimensions } from '@swimlane/ngx-charts/release/common/view-dimensions.helper';
import { ColorHelper } from '@swimlane/ngx-charts/release/common/color.helper';
import { id } from '@swimlane/ngx-charts/release/utils/id';
import { getUniqueXDomainValues } from '@swimlane/ngx-charts/release/common/domain.helper';


@Component({
  selector: 'app-line-chart',
  template: `
    <ngx-charts-chart
      [view]="[width, height]"
      [showLegend]="legend"
      [legendOptions]="legendOptions"
      [activeEntries]="activeEntries"
      [animations]="animations"
      (legendLabelClick)="onClick($event)"
      (legendLabelActivate)="onActivate($event)"
      (legendLabelDeactivate)="onDeactivate($event)">
      <svg:defs>
        <svg:clipPath [attr.id]="clipPathId">
          <svg:rect
            [attr.width]="dims.width + 10"
            [attr.height]="dims.height + 10"
            [attr.transform]="'translate(-5, -5)'"/>
        </svg:clipPath>
      </svg:defs>
      <svg:g [attr.transform]="transform" class="line-chart chart">
        <svg:g ngx-charts-x-axis
          *ngIf="xAxis"
          [xScale]="xScale"
          [dims]="dims"
          [showGridLines]="showGridLines"
          [showLabel]="showXAxisLabel"
          [labelText]="xAxisLabel"
          [tickFormatting]="xAxisTickFormatting"
          [ticks]="xAxisTicks"
          (dimensionsChanged)="updateXAxisHeight($event)">
        </svg:g>
        <svg:g ngx-charts-y-axis
          *ngIf="yAxis"
          [yScale]="yScale"
          [dims]="dims"
          [showGridLines]="showGridLines"
          [showLabel]="showYAxisLabel"
          [labelText]="yAxisLabel"
          [tickFormatting]="yAxisTickFormatting"
          [ticks]="yAxisTicks"
          [referenceLines]="referenceLines"
          [showRefLines]="showRefLines"
          [showRefLabels]="showRefLabels"
          (dimensionsChanged)="updateYAxisWidth($event)">
        </svg:g>
        <svg:g [attr.clip-path]="clipPath">
          <svg:g *ngFor="let series of localResults; trackBy:trackBy" [@animationState]="'active'">
            <svg:g ngx-charts-line-series
              [xScale]="xScale"
              [yScale]="yScale"
              [colors]="colors"
              [data]="series"
              [activeEntries]="activeEntries"
              [scaleType]="scaleType"
              [curve]="curve"
              [rangeFillOpacity]="rangeFillOpacity"
              [hasRange]="hasRange"
              [animations]="animations"
            />
          </svg:g>

          <svg:g *ngIf="!tooltipDisabled" (mouseleave)="hideCircles()">
            <svg:g ngx-charts-tooltip-area
              [dims]="dims"
              [xSet]="xSet"
              [xScale]="xScale"
              [yScale]="yScale"
              [results]="results"
              [colors]="colors"
              [tooltipDisabled]="tooltipDisabled"
              [tooltipTemplate]="seriesTooltipTemplate"
              (hover)="updateHoveredVertical($event)"
            />

            <svg:g *ngFor="let series of localResults">
              <svg:g ngx-charts-circle-series
                [xScale]="xScale"
                [yScale]="yScale"
                [colors]="colors"
                [data]="series"
                [scaleType]="scaleType"
                [visibleValue]="hoveredVertical"
                [activeEntries]="activeEntries"
                [tooltipDisabled]="tooltipDisabled"
                [tooltipTemplate]="tooltipTemplate"
                (select)="onClick($event, series)"
                (activate)="onActivate($event)"
                (deactivate)="onDeactivate($event)"
              />
            </svg:g>
          </svg:g>
        </svg:g>
      </svg:g>
      <svg:g ngx-charts-timeline
        *ngIf="timeline && scaleType != 'ordinal'"
        [attr.transform]="timelineTransform"
        [results]="results"
        [view]="[timelineWidth, height]"
        [height]="timelineHeight"
        [scheme]="scheme"
        [customColors]="customColors"
        [scaleType]="scaleType"
        [legend]="legend"
        (onDomainChange)="updateDomain($event)">
        <svg:g *ngFor="let series of localResults; trackBy:trackBy">
          <svg:g ngx-charts-line-series
            [xScale]="timelineXScale"
            [yScale]="timelineYScale"
            [colors]="colors"
            [data]="series"
            [scaleType]="scaleType"
            [curve]="curve"
            [hasRange]="hasRange"
            [animations]="animations"
          />
        </svg:g>
      </svg:g>
    </ngx-charts-chart>
  `,
  styleUrls: ['./line-chart.component.styl'],
  encapsulation: ViewEncapsulation.None,
  changeDetection: ChangeDetectionStrategy.OnPush,
  animations: [
    trigger('animationState', [
      transition(':leave', [
        style({
          opacity: 1,
        }),
        animate(500, style({
          opacity: 0
        }))
      ])
    ])
  ]
})
export class LineChartComponent extends BaseLineChartComponent {

  @Input() append = false;
  @Input() legend;
  @Input() legendTitle = 'Legend';
  @Input() xAxis;
  @Input() yAxis;
  @Input() showXAxisLabel;
  @Input() showYAxisLabel;
  @Input() xAxisLabel;
  @Input() yAxisLabel;
  @Input() autoScale;
  @Input() timeline;
  @Input() gradient: boolean;
  @Input() showGridLines = true;
  @Input() curve: any = curveLinear;
  @Input() activeEntries: any[] = [];
  @Input() schemeType: string;
  @Input() rangeFillOpacity: number;
  @Input() xAxisTickFormatting: any;
  @Input() yAxisTickFormatting: any;
  @Input() xAxisTicks: any[];
  @Input() yAxisTicks: any[];
  @Input() roundDomains = false;
  @Input() tooltipDisabled = false;
  @Input() showRefLines = false;
  @Input() referenceLines: any;
  @Input() showRefLabels = true;
  @Input() xScaleMin: any;
  @Input() xScaleMax: any;
  @Input() yScaleMin: number;
  @Input() yScaleMax: number;

  @Output() activate: EventEmitter<any> = new EventEmitter();
  @Output() deactivate: EventEmitter<any> = new EventEmitter();

  @ContentChild('tooltipTemplate') tooltipTemplate: TemplateRef<any>;
  @ContentChild('seriesTooltipTemplate') seriesTooltipTemplate: TemplateRef<any>;

  localResults: any[];
  dims: ViewDimensions;
  xSet: any;
  xDomain: any;
  yDomain: any;
  seriesDomain: any;
  yScale: any;
  xScale: any;
  colors: ColorHelper;
  scaleType: string;
  transform: string;
  clipPath: string;
  clipPathId: string;
  series: any;
  areaPath: any;
  margin = [10, 20, 10, 20];
  hoveredVertical: any; // the value of the x axis that is hovered over
  xAxisHeight = 0;
  yAxisWidth = 0;
  filteredDomain: any;
  legendOptions: any;
  hasRange: boolean; // whether the line has a min-max range around it
  timelineWidth: any;
  timelineHeight = 50;
  timelineXScale: any;
  timelineYScale: any;
  timelineXDomain: any;
  timelineTransform: any;
  timelinePadding = 10;

  update(): void {
    super.update();

    if (!this.localResults || !this.append) {
      this.localResults = this.results;
    } else {
      this.appendNewData();
    }

    this.dims = calculateViewDimensions({
      width: this.width,
      height: this.height,
      margins: this.margin,
      showXAxis: this.xAxis,
      showYAxis: this.yAxis,
      xAxisHeight: this.xAxisHeight,
      yAxisWidth: this.yAxisWidth,
      showXLabel: this.showXAxisLabel,
      showYLabel: this.showYAxisLabel,
      showLegend: this.legend,
      legendType: this.schemeType,
    });

    if (this.timeline) {
      this.dims.height -= (this.timelineHeight + this.margin[2] + this.timelinePadding);
    }

    this.xDomain = this.getXDomain();
    if (this.filteredDomain) {
      this.xDomain = this.filteredDomain;
    }

    this.yDomain = this.getYDomain();
    this.seriesDomain = this.getSeriesDomain();

    this.xScale = this.getXScale(this.xDomain, this.dims.width);
    this.yScale = this.getYScale(this.yDomain, this.dims.height);

    this.updateTimeline();

    this.setColors();
    this.legendOptions = this.getLegendOptions();

    this.transform = `translate(${ this.dims.xOffset } , ${ this.margin[0] })`;

    this.clipPathId = 'clip' + id().toString();
    this.clipPath = `url(#${this.clipPathId})`;
  }

  appendNewData(): void {
    for (let i = 0; i < this.results.length; ++i) {
      if (!this.localResults[i]) {
        this.localResults.push(this.results[i]);
      } else {
        this.appendDataToSeries(i);
      }
    }
  }

  appendDataToSeries(index: number): void {
    const lastSeries = this.localResults[index].series.slice(-1)[0];

    if (lastSeries) {
      const seriesIndex = this.results[index].series.map(i => i.name).indexOf(lastSeries.name);
      this.localResults[index].series.push(...this.results[index].series.slice(seriesIndex + 1));
    }
  }

  updateTimeline(): void {
    if (this.timeline) {
      this.timelineWidth = this.dims.width;
      this.timelineXDomain = this.getXDomain();
      this.timelineXScale = this.getXScale(this.timelineXDomain, this.timelineWidth);
      this.timelineYScale = this.getYScale(this.yDomain, this.timelineHeight);
      this.timelineTransform = `translate(${ this.dims.xOffset }, ${ -this.margin[2] })`;
    }
  }

  getXDomain(): any[] {
    let values = getUniqueXDomainValues(this.results);

    this.scaleType = this.getScaleType(values);
    let domain = [];

    if (this.scaleType === 'linear') {
      values = values.map(v => Number(v));
    }

    let min;
    let max;
    if (this.scaleType === 'time' || this.scaleType === 'linear') {
      min = this.xScaleMin
        ? this.xScaleMin
        : Math.min(...values);

      max = this.xScaleMax
        ? this.xScaleMax
        : Math.max(...values);
    }

    if (this.scaleType === 'time') {
      domain = [new Date(min), new Date(max)];
      this.xSet = [...values].sort((a, b) => {
        const aDate = a.getTime();
        const bDate = b.getTime();
        if (aDate > bDate) { return 1; }
        if (bDate > aDate) { return -1; }
        return 0;
      });
    } else if (this.scaleType === 'linear') {
      domain = [min, max];
      // Use compare function to sort numbers numerically
      this.xSet = [...values].sort((a, b) => (a - b));
    } else {
      domain = values;
      this.xSet = values;
    }

    return domain;
  }

  getYDomain(): any[] {
    const domain = [];
    for (const results of this.results) {
      for (const d of results.series) {
        if (domain.indexOf(d.value) < 0) {
          domain.push(d.value);
        }
        if (d.min !== undefined) {
          this.hasRange = true;
          if (domain.indexOf(d.min) < 0) {
            domain.push(d.min);
          }
        }
        if (d.max !== undefined) {
          this.hasRange = true;
          if (domain.indexOf(d.max) < 0) {
            domain.push(d.max);
          }
        }
      }
    }

    const values = [...domain];
    if (!this.autoScale) {
      values.push(0);
    }

    const min = this.yScaleMin
      ? this.yScaleMin
      : Math.min(...values);

    const max = this.yScaleMax
      ? this.yScaleMax
      : Math.max(...values);

    return [min, max];
  }

  getSeriesDomain(): any[] {
    return this.results.map(d => d.name);
  }

  getXScale(domain, width): any {
    let scale;

    if (this.scaleType === 'time') {
      scale = scaleTime()
        .range([0, width])
        .domain(domain);
    } else if (this.scaleType === 'linear') {
      scale = scaleLinear()
        .range([0, width])
        .domain(domain);

      if (this.roundDomains) {
        scale = scale.nice();
      }
    } else if (this.scaleType === 'ordinal') {
      scale = scalePoint()
        .range([0, width])
        .padding(0.1)
        .domain(domain);
    }

    return scale;
  }

  getYScale(domain, height): any {
    const scale = scaleLinear()
      .range([height, 0])
      .domain(domain);

    return this.roundDomains ? scale.nice() : scale;
  }

  getScaleType(values): string {
    let date = true;
    let num = true;

    for (const value of values) {
      if (!this.isDate(value)) {
        date = false;
      }

      if (typeof value !== 'number') {
        num = false;
      }
    }

    if (date) { return 'time'; }
    if (num) { return 'linear'; }
    return 'ordinal';
  }

  isDate(value): boolean {
    if (value instanceof Date) {
      return true;
    }

    return false;
  }

  updateDomain(domain): void {
    this.filteredDomain = domain;
    this.xDomain = this.filteredDomain;
    this.xScale = this.getXScale(this.xDomain, this.dims.width);
  }

  updateHoveredVertical(item): void {
    this.hoveredVertical = item.value;
    this.deactivateAll();
  }

  @HostListener('mouseleave')
  hideCircles(): void {
    this.hoveredVertical = null;
    this.deactivateAll();
  }

  onClick(data, series?): void {
    if (series) {
      data.series = series.name;
    }

    this.select.emit(data);
  }

  trackBy(index, item): string {
    return item.name;
  }

  setColors(): void {
    let domain;
    if (this.schemeType === 'ordinal') {
      domain = this.seriesDomain;
    } else {
      domain = this.yDomain;
    }

    this.colors = new ColorHelper(this.scheme, this.schemeType, domain, this.customColors);
  }

  getLegendOptions() {
    const opts = {
      scaleType: this.schemeType,
      colors: undefined,
      domain: [],
      title: undefined
    };
    if (opts.scaleType === 'ordinal') {
      opts.domain = this.seriesDomain;
      opts.colors = this.colors;
      opts.title = this.legendTitle;
    } else {
      opts.domain = this.yDomain;
      opts.colors = this.colors.scale;
    }
    return opts;
  }

  updateYAxisWidth({ width }): void {
    this.yAxisWidth = width;
    this.update();
  }

  updateXAxisHeight({ height }): void {
    this.xAxisHeight = height;
    this.update();
  }

  onActivate(item) {
    this.deactivateAll();

    const idx = this.activeEntries.findIndex(d => {
      return d.name === item.name && d.value === item.value;
    });
    if (idx > -1) {
      return;
    }

    this.activeEntries = [item];
    this.activate.emit({ value: item, entries: this.activeEntries });
  }

  onDeactivate(item) {
    const idx = this.activeEntries.findIndex(d => {
      return d.name === item.name && d.value === item.value;
    });

    this.activeEntries.splice(idx, 1);
    this.activeEntries = [...this.activeEntries];

    this.deactivate.emit({ value: item, entries: this.activeEntries });
  }

  deactivateAll() {
    this.activeEntries = [...this.activeEntries];
    for (const entry of this.activeEntries) {
      this.deactivate.emit({ value: entry, entries: [] });
    }
    this.activeEntries = [];
  }
}