adds latest route to api

in regards to #16: still needs to be documented on openapi.json

bin/build-coinbase-latest.mjs

@@ -0,0 +1,43 @@
+#!/usr/bin/env node --experimental-modules
+
+import { createReadStream, createWriteStream } from 'node:fs'
+import { mkdir } from 'node:fs/promises'
+import { EOL } from 'node:os'
+
+import { readCache, byExchange, readLastCachedJsonLineOf } from '../lib/cache.mjs'
+import { csvDateReplacer, jsonDateReviver } from '../lib/date.mjs'
+
+console.log('bin/build-coinbase-latest load: data/* ')
+
+try {
+  console.time('bin/build-coinbase-latest create: @api/latest.{format:json,csv} time')
+
+  await mkdir('www/api', { recursive: true })
+  console.log('bin/build-coinbase-latest exists: www/api/')
+
+  const latestJson = createWriteStream('www/api/latest.json')
+  latestJson.write('[')
+
+  const latestCsv = createWriteStream('www/api/latest.csv')
+  latestCsv.write('id,interval,date,open,high,low,close,volume' + EOL)
+
+  let isFirstLine = true
+  for (const file of await readCache(byExchange('coinbase'))) {
+    console.time(`→ load: ${file} appendLine: @api/latest.{format:json,csv} time`)
+    const lastCachedCandle = await readLastCachedJsonLineOf(createReadStream(file), jsonDateReviver)
+    const [, , id, interval] = file.split(/[/,.]/)
+    if (isFirstLine) {
+      isFirstLine = false
+      latestJson.write(JSON.stringify([id, interval, ...lastCachedCandle]))
+    } else {
+      latestJson.write(`,${JSON.stringify([id, interval, ...lastCachedCandle])}`)
+    }
+    latestCsv.write(`${id},${interval},${JSON.stringify(lastCachedCandle, csvDateReplacer).slice(1, -1).replaceAll('"', '')}${EOL}`)
+    console.timeEnd(`→ load: ${file} appendLine: @api/latest.{format:json,csv} time`)
+  }
+  latestJson.write(']' + EOL)
+} catch (error) {
+  console.error(error)
+} finally {
+  console.timeEnd('bin/build-coinbase-latest create: @api/latest.{format:json,csv} time')
+}

package.json

@@ -13,7 +13,7 @@
     "build-sitemap": "node --experimental-modules bin/build-sitemap.mjs",
     "build-coinbase": "node --experimental-modules bin/build-coinbase.mjs",
     "build-coinbase-history": "node --experimental-modules bin/build-coinbase-history.mjs",
-    "test": "NODE_V8_COVERAGE=coverage node --experimental-modules --test --test-reporter spec --experimental-test-coverage test",
+    "build-coinbase-latest": "node --experimental-modules bin/build-coinbase-latest.mjs",
     "watch": "serve www & node --experimental-modules --test --test-reporter dot --watch test & wait"
   },
   "author": "Ivo von Putzer Reibegg <[email protected]> (https://github.com/ivoputzer)",