Hashes all the files in the adjacent metadata folder.

Provenance.js

const fs = require("fs")
const crypto = require("crypto")

const processConcurrently = async (inputs, fetcher, concurrentRequests = 5, maxRetries = 3) => {
    let index = 0
    const output = Array(inputs.length)
    const worker = (ticket = false, retry = 0) => {
        if (!ticket) ticket = index++
        if (ticket >= inputs.length) return

        const input = inputs[ticket]
        return fetcher(input, ticket)
            .then(result => output[ticket] = result)
            .then(() => worker())
            .catch(() => retry <= maxRetries && worker(ticket, retry++))
    }

    await Promise.all(Array(concurrentRequests).fill().map(() => worker()))

    return output
}

const hashFile = path => new Promise((resolve, reject) => {
    const hash = crypto.createHash("sha256")
    const input = fs.createReadStream(path)
    input.on("error", reject)
    input.on("data", chunk => hash.update(chunk))
    input.on("close", () => resolve(hash.digest("hex")))
})

processConcurrently(
    fs.readdirSync(`${__dirname}/metadata`).map(file => `${__dirname}/metadata/${file}`),
    hashFile
).then(hashes => {
    // console.log(hashes)
    const hash = crypto.createHash("sha256")
    hashes.forEach(_hash => hash.update(_hash))
    console.log("Provenance hash:", hash.digest("hex"))
})