i18n Translation File Diff

You spent the week editing pt.json and now need to know what en.json still lacks before the deploy. Paste both files and the comparison comes back split into sections: missing keys, extra keys, blank values and a coverage bar in percent. At the end there is a JSON skeleton of the missing keys alone, with the same nested shape and empty values, ready to paste into the other locale file.

Both files are flattened into dot paths before anything is compared, so menu.file.open and items.0 become plain keys and nesting stops getting in the way. On top of that comes the placeholder check, which understands the common formats at once: {name}, {{name}}, {0}, %s, %d, %1$s, ${name}, :name, the numbered Trans tags and the variable name inside ICU plural and select blocks.

The failure that slips through is not the missing key, which usually prints the raw path on screen. It is the placeholder that vanished in translation: if the reference says Hi {name} and the translation says Olá, the argument is dropped in silence. Watch the structure conflicts too, where menu is an object on one side and a string on the other — libraries tend to return the object and the interface shows [object Object].