superfluous-key

Why this is bad

The source locale is the contract, so a key only a translation carries is usually a leftover from a message you renamed or deleted.

In rarer cases, the source locale is missing a message that your code actually uses. In that case, the raw key name is typically rendered for this locale.

Examples

Given a source locale that defines only save.

Examples of incorrect code for this rule:

{
  "save": "Guardar",
  "discard": "Descartar"
}

Examples of correct code for this rule:

{
  "save": "Guardar"
}

How to fix it

First, check why your source locale doesn't have the key:

• The key was renamed in the source locale: Rename the key in every target locale too, so its translations are kept.
• The key was removed in the source locale: Delete the key from all target locales too.
• The key is missing in the source locale: If the key is still referenced in source code, add it to your source locale too.

To be sure, it's worth checking your hypothesis against the accompanying source code.