I have a NodeJS project that uses BigInt for its model's ids. I also have a WebSocket where I sent serialized objects to a client. The problem with BigInt is that it is not serializable like other objects (Boolean, Number, etc). Therefore I use MDN recommendation to define a global handler function the BigInt object.
BigInt.prototype.toJSON = function() { return this.toString() }
I will use this in the entire app scope from now on.
The question is where do I place this code so it is elegant and respects SOLID principles?
I am looking for a good solution for kind of issue.
Currently it is placed in index.js like this:
import 'dotenv/config';
import cors from 'cors';
import express from 'express';
import logger from './middleware/logger';
const main = async () => {
// where should I modularise BigInt extension
BigInt.prototype.toJSON = function () {
return this.toString();
};
app.use(cors());
app.get('/', (req, res) => {
res.send('Hello World!');
});
app.listen(3000, () => console.log(`Example app listening on port 3000!`));
};
main().catch((err) => {
logger.error(err);
});
The best practice for this kind of extension is to use the solution for this question.
I've refactored the code like this.
utils.ts
(BigInt.prototype as any).toJSON = function () {
return this.toString();
};
index.ts
import 'dotenv/config';
import cors from 'cors';
import express from 'express';
import logger from './middleware/logger';
import "utils.ts" // <== this code gets executed, therefore BigInt extenstion is in the scope of project from now on
const main = async () => {
app.use(cors());
app.get('/', (req, res) => {
res.send('Hello World!');
});
app.listen(3000, () => console.log(`Example app listening on port 3000!`));
};
main().catch((err) => {
logger.error(err);
});