Stock Performance Grid in JavaScript

// Six tickers whose price levels differ by 40x: a shared y scale would
// flatten the cheap ones into noise, so this trellis uses
// `scales: { y: 'independent' }`. Each panel gets its own honest domain, and
// the panels are STILL pixel-aligned: the trellis measures every panel's
// axis-label gutter and pushes the widest as a shared floor, so the plot
// rectangles agree to the pixel and the shapes stay comparable.
//
// One toolbar for the grid: drag or wheel-zoom in any panel and every panel
// follows on the shared x window; reset restores all six at once.
//
// Deterministic OHLC walks so the e2e snapshot is stable.
function mulberry32(seed) {
  return function () {
    seed |= 0
    seed = (seed + 0x6d2b79f5) | 0
    var t = Math.imul(seed ^ (seed >>> 15), 1 | seed)
    t = (t + Math.imul(t ^ (t >>> 7), 61 | t)) ^ t
    return ((t ^ (t >>> 14)) >>> 0) / 4294967296
  }
}

function ohlcWalk(seed, start, vol) {
  var rand = mulberry32(seed)
  var r2 = function (v) {
    return Math.round(v * 100) / 100
  }
  var out = []
  var ts = new Date('01 Jan 2025').getTime()
  var close = start
  for (var i = 0; i < 40; i++) {
    var open = close
    close = Math.max(vol, open + (rand() - 0.48) * vol * 2)
    var high = Math.max(open, close) + rand() * vol
    var low = Math.max(vol * 0.2, Math.min(open, close) - rand() * vol)
    out.push({ x: ts, y: [r2(open), r2(high), r2(low), r2(close)] })
    ts += 86400000
  }
  return out
}

var TICKERS = [
  { ticker: 'ANVL', seed: 3, start: 24, vol: 0.9 },
  { ticker: 'BRCK', seed: 17, start: 61, vol: 2.1 },
  { ticker: 'CDER', seed: 29, start: 142, vol: 4.5 },
  { ticker: 'DELM', seed: 41, start: 310, vol: 9 },
  { ticker: 'ELMS', seed: 53, start: 78, vol: 2.6 },
  { ticker: 'FRST', seed: 67, start: 927, vol: 24 },
]

// One series NAME across the grid (the headers already name the tickers), so
// the shared legend has nothing to add and stays hidden.
var stockSeries = TICKERS.map(function (t) {
  return {
    name: 'OHLC',
    ticker: t.ticker,
    data: ohlcWalk(t.seed, t.start, t.vol),
  }
})

var options = {
  series: stockSeries,
  chart: {
    id: 'stockTrellis',
    type: 'candlestick',
    height: 620,
    animations: {
      enabled: false,
    },
  },
  trellis: {
    by: 'ticker',
    columns: 3,
    gap: 14,
    scales: {
      y: 'independent',
    },
  },
  xaxis: {
    type: 'datetime',
  },
  yaxis: {
    labels: {
      formatter: function (val) {
        return '$' + Math.round(val)
      },
    },
  },
  dataLabels: {
    enabled: false,
  },
  tooltip: {
    x: {
      format: 'dd MMM',
    },
  },
}

var chart = new ApexCharts(document.querySelector('#chart'), options)
chart.render()