Preprocess typescript files to make export/import statements work on appscript after compiling with ts2gs

ts2gs_preprocessing.js

// Preprocess typescript files to make export/import statements work on appscript after compiling with ts2gs

const fs = require('fs');
const path = require('path');
const glob = require("glob")
const ncp = require('ncp').ncp;

const source = path.join(__dirname, "..", "/lib");
const target = path.join(__dirname, "..", "/bin");

function copyAndGetFiles(){
    return new Promise((resolve,reject)=>{
        ncp(source, target, (err)=>{
            if(err) return reject(err);
            console.log("Copy lib into bin - OK")
            glob(target+ "/**/*.ts", {stopOnErr:true}, function (err, files) {
                if(err) return reject(err);
                console.log("Files found in lib -", files.length)
                return resolve(files)
            });
        });
    });
}

function processFile(file){
    return new Promise((resolve,reject)=>{
        fs.readFile(file, 'utf8', (err,data)=>{
            if(err) return reject(err);
            data=data.replace(/export(\ default)?\ /g, "");
            fs.writeFile(file, data, (err)=>{
                if(err) return reject(err);
                return resolve();
            });
        });
    })
}

function processFiles(){
    return copyAndGetFiles().then((files)=>{
        const promises=files.map((file)=>{
            return processFile(file);
        });
        return Promise.all(promises);
    });
}

processFiles().then(()=>{
    console.log("Preprocessing Finished");
}).catch((err)=>{
    console.error("Preprocessing Errored")
    throw err;
});