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https://github.com/lynchmarkHQ/lynchmark.com.git
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20 lines
727 B
JavaScript
20 lines
727 B
JavaScript
const createStreamVisualizer = async (iter, { maxPoints: M, alpha: A, width: W, height: H, yDomain: Y }) => {
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const { scaleLinear, line } = await import('https://cdn.jsdelivr.net/npm/d3@7/+esm')
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const D = []
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let E
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for await (const { timestamp: t, value: v } of iter) {
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E = E === undefined ? v : A * v + (1 - A) * E
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D.push({ timestamp: t, value: v, ema: E })
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if (D.length > M) D.shift()
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}
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if (!D.length) return { data: D, path: '' }
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const x = scaleLinear().domain([D[0].timestamp, D.at(-1).timestamp]).range([0, W])
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const y = scaleLinear().domain(Y).range([H, 0])
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const l = line().x(d => x(d.timestamp)).y(d => y(d.ema))
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return { data: D, path: l(D) }
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}
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export default createStreamVisualizer; |