About ngx-date-bar-chart

Since building charts in angular with dates on the x-axis (on a day interval) was a lot of work, we build our own easy to use and responsive chart that does all the annoying stuff for you.

We also added a really cool feature (see 'customDrawing'), where you have access to all parameters of our chart from the outside. This enables you to draw individual stuff with d3 directly on the chart, which was previously really complex and required hacking the code.

Demo and code repo

• for a quick demo, check out stackblitz
• code: github, including a demo project (same as on stackblitz):

Chart types

• simple bar chart with one bar per day
• bar series with multiple bars per day
• stacked bars for each day

Installation

npm install ngx-date-bar-chart

Usage

In your module add NgxDateBarChartModule to the imports:

@NgModule({
  declarations: [
    AppComponent
  ],
  imports: [
    BrowserModule,
    NgxDateBarChartModule
  ],
  providers: [],
  bootstrap: [AppComponent]
})

Simple Example

You can check out more examples in the demo project, for this just head over to github and build the demo :)

1. Set up some data

const data: INgxDateValue[] = [];
const today = new Date();

for (let i = 0; i < 15; ++i) {
  const date = new Date(today);
  date.setDate(today.getDate() + i);
  data.push({
    new Date(date),
    value: i * i,
  });
}

2. Use the chart in you html-template and maybe add some nice colors

<ngx-date-bar-chart
  [colors]="['navy', 'dodgerblue']"
  [data]="data"
></ngx-date-bar-chart>

3. If you want multiple values per day just change the type of data to 'INgxDateValueSeries[]' and you are good to go:

const data: INgxDateValueSeries[] = [];
const today = new Date();

for (let i = 0; i < 15; ++i) {
  const date = new Date(today);
  date.setDate(today.getDate() + i);
  data.push({
    new Date(date),
    values: [i, 2*i, 3 * i],
  });
}

4. If you want your data stacked, just set the stacked attribute in the html-template.

<ngx-date-bar-chart
  [colors]="['navy', 'dodgerblue']"
  [data]="data"
  [stacked]="true"
></ngx-date-bar-chart>

Customization aka inputs

Use these inputs to style the chart the way you want it

data and chart type

data: INgxDateValue[] | INgxDateValueSeries[] aka the 'input', has to be set

stacked: boolean whether the chart is stacked or not

bars, padding, and colors

barSpacingPercentage: number amount of space that is distributed between the bars as space (range from 0 to 1)

barSeriesInnersSpacing: number only relevant for series; amount of space that is distributed between the bars for each date

rounded: boolean: whether the bars are rounded (defaults to true)

barRadiusFunction: ((barWidth: number) => number) use this, if you want your bar-radius to be custom

colors: string[] set some nice colors, if more colors are present than required (e.g. single bars and two colors) they just repeat

domains

yMax: number set a maximum y-value (all higher values are clamped)

yMin: number set a minimum y-value (e.g. 0, all lower values will be clamped). If the type is stacked, 0 is default

xMax: Date set a maximum x-value (all higher values are clamped)

xMin: Date set a minimum x-value (all lower values are clamped)

labels, axis, and ticks

formatDateFunction: ((date: Date) => string) use this to format the x-axis dates the way you want them

fixedXTicks: Date[] use specific x-ticks instead of the automatically generated ones

fixedYTicks: number[] same as x-ticks

minSpacePerXTick: number minimum amount of space required to display an x tick (in px)

legendLabels: string[] list of the legend labels for each data row

legendPosition: LegendPosition position of the legend (e.g. BottomLeft (default))

xAxisLabel: string label for the x-axis

yAxisLabel: string label for the y-axis

xAxisHeight: number height of the x-axis (aka space for the ticks and the x-axis-label)

yAxisWidth: number width of the y-axis (aka space for the ticks and the y-axis-label)

fontSizeTicks: string font size of ticks and axis-descriptions

custom horizontal line

usage

[horizontalLine]="{yValue: 20, color: '#40088BFF', widthPx: 2}"

attributes

yValue: number (required)

color: hexString (required)

widthPx: number (required)

custom drawings

customDrawing: ((
  boundingSvgSelection: any,
  fullWidth: number,
  fullHeight: number,
  chartHeight: number,
  chartWidth: number,
  barWidth: number,
  padding: { top: number; left: number; right: number; bottom: number },

  xScale: any,
  yScale: any,

  dataSingle: INgxDateValue[],
  dataSeries: INgxDateValueSeries[],
  xDomain: [Date, Date],
  yDomain: [number, number]
) => void

With this method you can draw on the chart yourself and access internal variables like chartWidth or xScale (for more info on scales consult the d3 docs). Having access to e.g. the chart-width and chart-height enables you to draw a custom trendline. To illustrate this functionality, the following code draws a line from the top left corner of the chart, to the top of the bar that is exactly in the middle. This makes no sense, but it demonstrates, how simple it is to add your custom stuff.

customDrawing = (
boundingSvgSelection: any,

    fullWidth: number,
    fullHeight: number,
    chartHeight: number,
    chartWidth: number,
    barWidth: number,
    padding: { top: number; left: number; right: number; bottom: number },

    xScale: any,
    yScale: any,

    dataSingle: INgxDateValue[],
    dataSeries: INgxDateValueSeries[],
    xDomain: [Date, Date],
    yDomain: [number, number]

) => {
// lazy removal of all stuff (so it won't get rendered twice
boundingSvgSelection
.selectAll('.custom-after-rendering')
.selectAll('line')
.remove();

    /*
     *  append a red line
     *  use the other g containers to render the line on the level you want
     *  'custom-before-rendering'
     *  'custom-between-bar-and-axis'
     *  'custom-after-rendering'
     */
    boundingSvgSelection
      .selectAll('.custom-after-rendering')
      .append('line')
      .style('stroke', 'red')
      .style('stroke-width', 3)
      .attr('x1', padding.left)
      .attr('y1', padding.top)
      .attr(
        'x2',
        padding.left +
          xScale(dataSingle[Math.floor(dataSingle.length / 2)].date)
      )
      .attr(
        'y2',
        padding.top +
          yScale(dataSingle[Math.floor(dataSingle.length / 2)].value)
      );

};

All you need to do now, is to pass the function in the html template like this: [customDrawing]="customDrawing" :)