Incorrect Unicode space character in return value from Date.prototype.toLocaleTimeString

[jbgomez]

Details

The space character immediately preceding "AM"/"PM" in the return value is a Unicode "NARROW NO-BREAK SPACE" (8239) character, instead of the correct "SPACE" (32) character.

Affects Date.prototype.toLocaleTimeString and Date.prototype.toLocaleString.

Node.js version

v18.13.0

Example code

let localeString = new Date().toLocaleString(); // e.g., "1/6/2023, 2:10:22 PM"
let lastThreeChars = localeString.slice(-3); // e.g., " PM"
lastThreeChars.charCodeAt(0); // 8239 (but should be 32)

Operating system

macOS 12.5.1 (21G83)

Scope

Runtime

Module and version

Not applicable.

[and-who]

I think in this Case the "NARROW NO-BREAK SPACE" (Char 8239) is more likely to be the "correct" space character.
Because you don't want to LineBreak between the Time and "AM/PM".

If you have trouble with your Snapshot Tests (I had some) be sure to keep your lokal and CI node Version in sync.
My Problem was, that I used 18.12.1 local and on the Test Server I just configured a Node:18 Docker Image (which resolved to 18.13.0).

So there are two Options:

1. Upgrade your lokal Setup to 18.13.0
2. use a more specific Docker Image in the CI Pipeline, e.g. node:18.12.1

[e3dio]

Ok who put CharCode 8239 into the toLocaleTimeString() function ?? You broke my terminal output:

Web Browser Chrome does not do this, it uses standard space char 32

Update: I changed my terminal font from Courier New to different font and it displays space correctly, but I don't like these other fonts, and other fonts also have error. Ended up slicing and modifying the string :P

[andersk]

This seems to have been a deliberate change in

• deps: update ICU to 72.1 node#45068

See also

• Error Date.toLocaleString() in node 19.0.0 node#45171

[jd1378]

Well this is causing quite a lot of trouble for a lot of people, by causing hydration mismatch in frameworks that hydrate on client side

[richardlau]

This was fixed in Node.js 18.15.0 by nodejs/node@492fc95bdf.