superfluous-key

error

Flags a key that a target locale defines but the source locale doesn't.

Why this is bad

The source locale is the contract, so a key only a translation carries never renders. It's usually a leftover from a message you renamed or deleted.

Given a source locale that defines only save.

Examples of incorrect code for this rule:

messages/es.json

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

Examples of correct code for this rule:

messages/es.json

{
  "save": "Guardar"
}