log-update.ts

import {type Writable} from 'node:stream';
import ansiEscapes from 'ansi-escapes';
import cliCursor from 'cli-cursor';

export type LogUpdate = {
	clear: () => void;
	done: () => void;
	(str: string): void;
};

const create = (stream: Writable, {showCursor = false} = {}): LogUpdate => {
	let previousLineCount = 0;
	let previousOutput = '';
	let hasHiddenCursor = false;

	const render = (str: string) => {
		if (!showCursor && !hasHiddenCursor) {
			cliCursor.hide();
			hasHiddenCursor = true;
		}

		const output = str + '\n';
		if (output === previousOutput) {
			return;
		}

		previousOutput = output;
		stream.write(ansiEscapes.eraseLines(previousLineCount) + output);
		previousLineCount = output.split('\n').length;
	};

	render.clear = () => {
		stream.write(ansiEscapes.eraseLines(previousLineCount));
		previousOutput = '';
		previousLineCount = 0;
	};

	render.done = () => {
		previousOutput = '';
		previousLineCount = 0;

		if (!showCursor) {
			cliCursor.show();
			hasHiddenCursor = false;
		}
	};

	return render;
};

const logUpdate = {create};
export default logUpdate;