Function tail

src/bin/tail.ts:21–67

(inputs: NodeJS.ReadableStream[], output: NodeJS.WritableStream, numlines: number, code: number)

// secondly for when we've reached EOF.

function tail(inputs: NodeJS.ReadableStream[], output: NodeJS.WritableStream, numlines: number, code: number): void {
	'use strict';
	if (!inputs || !inputs.length) {
		process.exit(code);
		return;
	}

	let current = inputs[0];
	inputs = inputs.slice(1);
	let n = 0;
	let outstanding = 0;
	let linebuffer: string[] = [];
	if (!current) {
		// use setTimeout to avoid a deep stack as well as
		// cooperatively yield
		setTimeout(tail, 0, inputs, output, numlines, code);
		return;
	}

	current.on('readable', function(): void {
		let rl = readline.createInterface({
			input: current,
			output: null
		});

		rl.on('line', (line: string) => {
			n++;
			linebuffer.push(line);
			if (n > numlines) {
				linebuffer.shift();
			}
		});
	});

	// FIXME: this only works for the case of a single input file
	current.on('end', function(): void {
		outstanding = linebuffer.length;
		for (let i = 0; i < linebuffer.length; i++) {
			output.write(linebuffer[i] + "\n", () => {
				outstanding--;
				if (!outstanding)
					process.exit(0);
			});
		}
		//setTimeout(tail, 0, inputs, output, numlines, code);
	});
}

function main(): void {
	'use strict';