From NextJS to SvelteKit ⚡

[PlopTheReal]

Just wanted to share my experience of migrating from a complete optimized NextJS+MobX CMS to SvelteKit and so far it's brilliant.
The reasons are that I'm focusing on reducing the data across the wire.
I still got a lot to do but at the moment of writing the size of the app (same features/pages comparison) has been reduce 3-4 times. 💪

[PlopTheReal]

In case that can help some of you, here is an example of the logic I wrote to upload files:

import busboy from 'busboy';
import { pipeline } from 'stream/promises';

export const post = async ({ request }) => {
    const content = request.headers.get('content-type');
    var percent = 0
    var bytes = ""

    var itemsCounter = 0, finished = false
    let contentLenght = request.headers.get('content-length')
    let contentLenghtKB = Math.round(contentLenght / 1024)
    let uploadedSize = 0
    var jobDone, jobRejected;
    var task = new Promise(function (resolve, reject) {
        jobDone = resolve;
        jobRejected = reject;
    });


    const bb = busboy({
        headers: {
            'content-type': content
        }
    });
    bb.on('file', async (name, file, info, mimetype) => {
        const { filename, encoding, mimeType } = info;
        console.log(
            `File [${name}]: filename: %j, encoding: %j, mimeType: %j`,
            filename,
            encoding,
            mimeType
        );

        ++itemsCounter
        let buffers = []

        file.on('data', data => {
            buffers.push(data);
            uploadedSize += data.length
            percent = Math.round(uploadedSize / contentLenght * 100)
            bytes = `${Math.round(uploadedSize / 1024)} / ${contentLenghtKB}`
        })
        file.on('end', async () => {
            try {

                const file= Buffer.concat(buffers)
                // DO WHATEVER YOU NEED WITH THE FILE
                // I GIVE IT TO SHARP TO COMPRESS IMAGES OR FFMPEG FOR VIDEOS
                if (--itemsCounter === 0 && finished) {
                    console.log('ALL DONE');
                    jobDone()
                }
            }
            catch (err) {
                console.error(err)
                jobRejected(err)
            }
        })


    });
    bb.on('field', (name, val, info) => {
        console.log(`Field [${name}]: value: %j`, val);
    });
    bb.on('finish', () => {
        finished = true;
        console.log('Done parsing form!');
    });

    await pipeline(request.body, bb);
    const error = await task

    if (error){
        return{
            status: 500,
            body: error
        }
    }
    return {
        status: 200
    };
};

Don't hesitate if you spot something that could be improved!

svelte version: 1.0.0-next.369