Download Module on NPM start - node.js

Question

I want to know if there is a easy way to download file before other code runs. I need file.js to be downloaded first from my server because I am requiring it in my app on different places. I know I can do something like that.
let file = fs.createWriteStream(path.join(__dirname, 'file.js'));
let request = http.get("http://expample.com/file.js",
function(response) {
response.pipe(file);
});
But if I assume correctly, the file is written asynchronously. So when I require that file I have just empty object or error.
So what is the best way to download that file synchronously at first on npm start?

Answer 1

You can get such result using npm script pre hooks.
Assuming your start-up script is called "start" , in your package.json add
script called "prestart" in wich you want to run script that executes file downloading. and in will be automatically run when you call npm run start
For example:
package.json :
{
"name": "test",
"version": "1.0.0",
"description": "",
"main": "index.js",
"scripts": {
"start": "node index.js",
"prestart": "node pre-start.js"
},
"author": "",
"license": "ISC"
}
index.js:
const value = require('./new-file.json');
console.log(value);
pre-start.js:
const fs = require('fs');
setTimeout(function() {
const value = {
"one" : 1,
"two" : 2
};
fs.writeFileSync('new-file.json', JSON.stringify(value));
}, 1000)
Here is a link to article with more detailed information:
http://www.marcusoft.net/2015/08/pre-and-post-hooks-for-npm-scripting.html
The other way is to run your other code after file is written:
let file = fs.createWriteStream(path.join(__dirname, 'file.js'));
let request = http.get("http://expample.com/file.js",
function(response) {
response.pipe(file);
file.on('finish',function(){
// run your code here
}
});