I am trying to create a post object which stores the id, title, and comments associated with the post. For now, I am storing data in a variable. When I initialize that variable (Line 7), posts = { }, it works but for posts = [ ] it returns empty array to the frontend.
const express = require('express');
const bodyParser = require('body-parser');
const cors = require('cors');
const app = express();
app.use(bodyParser.json());
app.use(cors());
const posts = [];
app.get('/posts', (req, res) => {
console.log(posts);
res.send(posts);
});
app.post('/events', (req, res) => {
const { type, data } = req.body;
if (type == 'PostCreated') {
const { id, title } = data;
posts[id] = {
id,
title,
comments: [],
};
}
if (type == 'CommentCreated') {
const { id, content, postId } = data;
const post = posts[postId];
post.comments.push({ id, content });
}
res.send({ status: 'Event Received' });
});
app.listen(4002, (req, res) => {
console.log('Listening on Port 4002');
});
posts can be an array if it is mutated like an array, but if send is bound to enumerate an array parameter in order to serialize it. A prop that's set on the array like posts["some id"] won't count in length, won't be enumerated when it is serialized.
if (type == 'PostCreated') {
const { id, title } = data;
// if posts is an array
posts.push({
id,
title,
comments: [],
});
}
To see it not work...
let props = [];
let id = "some id";
props[id] = "I'll be lost in serialization";
console.log(props.length); // 0