diff --git a/lib/utils/tty.coffee b/lib/utils/tty.coffee
deleted file mode 100644
index 20f9dae5..00000000
--- a/lib/utils/tty.coffee
+++ /dev/null
@@ -1,66 +0,0 @@
-
-windowSize = {}
-
-updateWindowSize = ->
-	size = require('window-size')?.get()
-	windowSize.width = size?.width
-	windowSize.height = size?.height
-
-process.stdout.on('resize', updateWindowSize)
-
-module.exports = (stream = process.stdout) ->
-	# make sure we get initial metrics
-	updateWindowSize()
-
-	currentWindowSize = ->
-		# always return a copy.
-		# width/height can be undefined if no TTY.
-		width: windowSize.width
-		height: windowSize.height
-
-	hideCursor = ->
-		stream.write('\u001B[?25l')
-
-	showCursor = ->
-		stream.write('\u001B[?25h')
-
-	cursorUp = (rows = 0) ->
-		stream.write("\u001B[#{rows}A")
-
-	cursorDown = (rows = 0) ->
-		stream.write("\u001B[#{rows}B")
-
-	cursorHidden = ->
-		Promise = require('bluebird')
-		Promise.try(hideCursor).disposer(showCursor)
-
-	write = (str) ->
-		stream.write(str)
-
-	writeLine = (str) ->
-		stream.write("#{str}\n")
-
-	clearLine = ->
-		stream.write('\u001B[2K\r')
-
-	replaceLine = (str) ->
-		clearLine()
-		write(str)
-
-	deleteToEnd = ->
-		stream.write('\u001b[0J')
-
-	return {
-		stream
-		currentWindowSize
-		hideCursor
-		showCursor
-		cursorHidden
-		cursorUp
-		cursorDown
-		write
-		writeLine
-		clearLine
-		replaceLine
-		deleteToEnd
-	}
diff --git a/lib/utils/tty.ts b/lib/utils/tty.ts
new file mode 100644
index 00000000..2efc0237
--- /dev/null
+++ b/lib/utils/tty.ts
@@ -0,0 +1,68 @@
+import * as Bluebird from 'bluebird';
+
+const windowSize: { width?: number; height?: number } = {};
+
+const updateWindowSize = () => {
+	const size = require('window-size')?.get();
+	windowSize.width = size?.width;
+	windowSize.height = size?.height;
+};
+
+process.stdout.on('resize', updateWindowSize);
+
+export = (stream: NodeJS.WriteStream = process.stdout) => {
+	// make sure we get initial metrics
+	updateWindowSize();
+
+	const currentWindowSize = () => {
+		// always return a copy.
+		// width/height can be undefined if no TTY.
+		return {
+			width: windowSize.width,
+			height: windowSize.height,
+		};
+	};
+
+	const hideCursor = () => stream.write('\u001B[?25l');
+
+	const showCursor = () => stream.write('\u001B[?25h');
+
+	const cursorUp = (rows: number = 0) => stream.write(`\u001B[${rows}A`);
+
+	const cursorDown = (rows: number = 0) => stream.write(`\u001B[${rows}B`);
+
+	const cursorHidden = () => {
+		const Promise = require('bluebird') as typeof Bluebird;
+		return Promise.try(hideCursor).disposer(() => {
+			showCursor();
+		});
+	};
+
+	const write = (str: string) => stream.write(str);
+
+	const writeLine = (str: string) => stream.write(`${str}\n`);
+
+	const clearLine = () => stream.write('\u001B[2K\r');
+
+	const replaceLine = (str: string) => {
+		clearLine();
+		return write(str);
+	};
+
+	const deleteToEnd = () => stream.write('\u001b[0J');
+
+	return {
+		stream,
+		currentWindowSize,
+		hideCursor,
+		showCursor,
+		cursorHidden,
+		cursorUp,
+		cursorDown,
+		write,
+		writeLine,
+		clearLine,
+		replaceLine,
+		deleteToEnd,
+	};
+};