JavaScript async generator/reader/transformer

fetch.js

const genline = async (i) => [Date.now(), i, "CRITICAL", "gui", ": asfd asdf asdf asdf asdf asdf asdf asdf asdf asdf asdf asdf asdf"].join(" ")

const generate = amount => {
	let arr = [];
	for(let i = 0; i < amount; i++) {
		arr.push(genline(i))
	}
	return arr
}

const transformer = {
	decoder: new TextDecoder(),
	lastString: '',
	transform: function(chunk, controller) {
		const string = `${this.lastString}${this.decoder.decode(chunk)}`;
		const lines = string.split(/\r\n|[\r\n]/g);
		this.lastString = lines.pop() || ''; 
		for (const line of lines) {
			controller.enqueue(line)
		}
	},
	flush: function(controller) {
	    if(this.lastString) controller.enqueue(this.lastString)
	}
}

const url = async amount => 
	URL.createObjectURL(
		new Blob([(await Promise.all(generate(amount))).join("\n")], {type: 'text/plain'}
	)
)
const getme = async (amount, fn) => 
	fetch(await url(amount))
	.then(rs => rs.body)
	.then(rs => rs.pipeThrough(new TransformStream(transformer)))
	.then(rs => rs.getReader())
	.then(async reader => {
		while(true){
			const {done, value} = await reader.read(); 
			if(done) break;
			fn(value)
		}
	}
)

getme(100000, res => document.body.innerText = res)