microting/ngx-charts

import { scaleLinear, scalePoint, scaleTime } from 'd3-scale';

export function getDomain(values, scaleType, autoScale, minVal?, maxVal?): number[] {
    let domain: number[] = [];
    if (scaleType === 'linear') {
      values = values.map(v => Number(v));
      if (!autoScale) {
        values.push(0);
      }
    }
    
    if (scaleType === 'time' || scaleType === 'linear') {
      const min = minVal ? minVal : Math.min(...values);
      const max = maxVal ? maxVal : Math.max(...values);

      domain = [min, max];
    } else {
      domain = values;
    }

    return domain;
}

export function getScale(domain, range: number[], scaleType, roundDomains): any {
  let scale: any;

  if (scaleType === 'time') {
    scale = scaleTime()
      .range(range)
      .domain(domain);
  } else if (scaleType === 'linear') {
    scale = scaleLinear()
      .range(range)
      .domain(domain);

    if (roundDomains) {
      scale = scale.nice();
    }
  } else if (scaleType === 'ordinal') {
    scale = scalePoint()
      .range([range[0], range[1]])
      .domain(domain);
  }

  return scale;
}