serialize highland streams

promises-streams.js

const fs = require("fs")
const _ = require("highland")

const files = [
    ".editorconfig",
    ".eslintrc"
]

function usePromises() {
    const promises = files.map(file => {
        return new Promise((resolve, reject) => {
            fs.readFile(file, "utf8", (err, data) => {
                if (err) {
                    reject()
                } else {
                    resolve(data)
                }
            })
        })
    })

    function resolvePromises(index) {
        if (index < promises.length) {
            Promise.resolve(promises[index]).then(data => {
                console.log(data)
                resolvePromises(index + 1)
            })
        }
    }

    resolvePromises(0)
}

function useStreams() {
    const readFile = _.wrapCallback(fs.readFile)
    const filesStream = _(files)

    filesStream
        .map(readFile)
        .sequence()
        .map(upperCase)
        .pipe(process.stdout)

    function upperCase(data) {
        return data.toString().toUpperCase()
    }
}
useStreams()
// usePromises()