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