From 12f34eb210f723b8d40f2ecd03afe289848ba64c Mon Sep 17 00:00:00 2001
From: David Lechner <david@pybricks.com>
Date: Tue, 1 Mar 2022 14:42:45 -0600
Subject: [PATCH] utils: add new timestamp function

This will be used to create suggested file names that include a timestamp.
---
 src/utils/index.test.ts | 20 +++++++++++++++++++-
 src/utils/index.ts      | 11 +++++++++++
 2 files changed, 30 insertions(+), 1 deletion(-)

diff --git a/src/utils/index.test.ts b/src/utils/index.test.ts
index 09b19f59..fb80543b 100644
--- a/src/utils/index.test.ts
+++ b/src/utils/index.test.ts
@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: MIT
 // Copyright (c) 2020 The Pybricks Authors
 
-import { assert, defined, ensureError, hex, maybe } from '.';
+import { assert, defined, ensureError, hex, maybe, timestamp } from '.';
 
 test('assert', () => {
     const assertTrue = jest.fn(() => assert(true, 'should not throw'));
@@ -44,3 +44,21 @@ test('ensureError', () => {
     stringToError.toHaveProperty('name', 'Error');
     stringToError.toHaveProperty('message', stringToErrorMessage);
 });
+
+describe('timestamp', () => {
+    it('should not contain spaces', () => {
+        expect(timestamp()).not.toContain(' ');
+    });
+
+    it('should not contain colons', () => {
+        expect(timestamp()).not.toContain(':');
+    });
+
+    it('should not contain periods', () => {
+        expect(timestamp()).not.toContain('.');
+    });
+
+    it('should not contain letters', () => {
+        expect(timestamp()).not.toMatch(/[A-Za-z]/);
+    });
+});
diff --git a/src/utils/index.ts b/src/utils/index.ts
index d85b9bda..23c8297b 100644
--- a/src/utils/index.ts
+++ b/src/utils/index.ts
@@ -63,3 +63,14 @@ export function ensureError(err: unknown): Error {
 
     return Error(String(err));
 }
+
+/**
+ * Gets a timestamp with second resolution suitable for use in a filename.
+ */
+export function timestamp(): string {
+    return new Date()
+        .toISOString()
+        .replace('T', '_')
+        .replaceAll(':', '-')
+        .replace(/\..*$/, '');
+}