# Check if a date is today

Compare the UTC calendar day of a date-time with the current one.

Canonical: https://1loc.dev/validator/check-if-a-date-is-today/
Version: 1.0.0
Runtime: JavaScript · Node.js 22 / modern browsers
Verification: Local fixtures; no external services
Updated: 2026-10-28

## Implementation

```javascript
function isToday({ dateTime, now }) { return new Date(dateTime).toISOString().slice(0, 10) === new Date(now).toISOString().slice(0, 10); }
```

## Input

```json
{
  "dateTime": "2026-10-28T09:00:00Z",
  "now": "2026-10-28T23:59:00Z"
}
```

## Expected output

```json
true
```

## Edge case

Input:
```json
{
  "dateTime": "2026-10-28T23:30:00-03:00",
  "now": "2026-10-28T12:00:00Z"
}
```
Output:
```json
false
```

## Limits

- now is an input so the result is testable; pass new Date().toISOString() in your code.
- “Today” is the UTC day, as in the original: a local evening can already be tomorrow, as the edge case shows.

The lab validates types and size before calling this function. Add equivalent validation at your own trust boundary.

## Source and license

Original: https://github.com/phuocng/1loc/blob/14b481cf60dff1620ab1bb99a43b1f68068cdd9b/contents/check-if-a-date-is-today.mdx
Author: Nguyen Huu Phuoc and original contributors
Contributors: See original repository history
Source commit: 14b481cf60dff1620ab1bb99a43b1f68068cdd9b
Copyright (c) 2020 phuoc-ng
License: MIT — https://1loc.dev/licenses/
Maintainer: Oveyon
Modifications: Takes the current time as an explicit input so the result is reproducible; compares UTC days as the original did. Original MDX retained as inert source evidence.