Promisified powershell child process

powershell.js

function powershell(commands) {
    return new Promise(function (resolve, reject) {
        const spawn = require("child_process").spawn
        const child = spawn("powershell.exe", ["-Command", "-"])
        const result = [], errors = []

        child.stdout.on("data", data => {
            result.push(data.toString())
        })

        child.stderr.on("data", data => {
            errors.push(data.toString())
        })

        child.on("exit", () => {
            console.log("Powershell Script finished")
            if (errors.length === 0) resolve(result)
            else reject(errors)
        })

        commands.forEach(cmd => {
            child.stdin.write(cmd + '\n')
        })

        child.stdin.end()
    })
}