Dasemu
1dae56415c
React + Vite frontend with a local-JSON-backed API (Vite middleware) for tracking portfolio holdings, contributions/withdrawals, recurring contribution plans, and a forecast chart comparing the portfolio's real value against a same-contributions S&P 500 benchmark. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
34 lines
1.3 KiB
JavaScript
34 lines
1.3 KiB
JavaScript
// Refreshes data/sp500.json with daily S&P 500 close prices from Yahoo Finance's
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// public chart endpoint (no API key required). Run with: node scripts/fetch-sp500.mjs
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import { writeFileSync } from "node:fs";
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import { fileURLToPath } from "node:url";
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import { dirname, join } from "node:path";
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const __dirname = dirname(fileURLToPath(import.meta.url));
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const OUT_PATH = join(__dirname, "..", "data", "sp500.json");
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const URL =
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"https://query1.finance.yahoo.com/v8/finance/chart/%5EGSPC?range=10y&interval=1d";
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const res = await fetch(URL, { headers: { "User-Agent": "Mozilla/5.0" } });
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if (!res.ok) {
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throw new Error(`Yahoo Finance request failed: ${res.status} ${res.statusText}`);
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}
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const data = await res.json();
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const result = data?.chart?.result?.[0];
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if (!result) {
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throw new Error("Unexpected response shape from Yahoo Finance");
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}
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const { timestamp } = result;
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const closes = result.indicators.quote[0].close;
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const series = [];
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for (let i = 0; i < timestamp.length; i++) {
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if (closes[i] == null) continue;
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const date = new Date(timestamp[i] * 1000).toISOString().slice(0, 10);
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series.push({ date, close: Number(closes[i].toFixed(2)) });
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}
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writeFileSync(OUT_PATH, JSON.stringify({ source: "yahoo-finance:^GSPC", updatedAt: new Date().toISOString(), series }, null, 2));
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console.log(`Wrote ${series.length} points to ${OUT_PATH}`);
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