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https://github.com/multipleof4/lynchmark.git
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48 lines
1.3 KiB
JavaScript
48 lines
1.3 KiB
JavaScript
export async function createStreamVisualizer(asyncIterable, options = {}) {
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const {
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maxPoints = 500,
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alpha = 0.2,
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width = 800,
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height = 300,
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yDomain = [0, 1]
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} = options
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const d3 = await import('https://cdn.jsdelivr.net/npm/d3@7/+esm')
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const cap = Math.max(1, maxPoints | 0)
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const a = Math.min(1, Math.max(0, Number(alpha)))
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const data = []
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let prevEma
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for await (const item of asyncIterable) {
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const timestamp = Number(item?.timestamp)
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const value = Number(item?.value)
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if (!Number.isFinite(timestamp) || !Number.isFinite(value)) continue
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prevEma = prevEma === undefined ? value : a * value + (1 - a) * prevEma
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data.push({ timestamp, value, ema: prevEma })
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if (data.length > cap) data.splice(0, data.length - cap)
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}
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if (!data.length) return { data, path: '' }
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const first = data[0].timestamp
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const last = data[data.length - 1].timestamp
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const x0 = first === last ? first - 1 : first
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const x1 = first === last ? last + 1 : last
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const x = d3.scaleLinear().domain([x0, x1]).range([0, width])
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const y = d3.scaleLinear().domain(yDomain).range([height, 0])
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const path =
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d3.line()
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.x(d => x(d.timestamp))
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.y(d => y(d.ema))(data) || ''
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return { data, path }
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}
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export default createStreamVisualizer;
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// Generation time: 4.457s
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// Result: PASS
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