Main Process vs Renderer Process Timezone Handling in Electron

Timezone Consistency Between Main and Renderer Processes

Developers building Electron applications often need to format dates and times according to the user's regional settings in both the main and renderer processes. The goal is to obtain identical timezone information from Intl.DateTimeFormat in each process so that displayed timestamps remain consistent regardless of where the formatting occurs.

However, Electron bundles its own ICU data while the renderer can also rely on the host operating system's ICU, and the main process's locale set via app.setLocale does not automatically propagate to the renderer. This creates uncertainty about whether the two processes will always resolve the same timezone offset, especially on Linux distributions that use separate ICU packages or when the app is packaged with asar, which locks the bundled ICU version at build time.

Should Electron enforce the use of its bundled ICU in the renderer to guarantee parity, or is it acceptable to let the renderer follow the host ICU with explicit locale propagation? What steps can developers take to verify and synchronize timezone data across processes without modifying Electron's core?