MARKLESS_REPEAT_KEY_DUPLICATE

Two items in an @for list produced the same key.

Error from the runtime, while a page renders or runs.

What happened

Two rows in the list have the same key, so Markless cannot tell them apart.

The error message reads:

MARKLESS_REPEAT_KEY_DUPLICATE: Duplicate @for key <keyText> from <source>.
The key is each row identity across reorder, insert, delete, and resume; duplicate identities make row state and DOM ownership ambiguous.
https://markless.dev/errors/MARKLESS_REPEAT_KEY_DUPLICATE

Words in angle brackets change from case to case.

How to fix it

Pick a key field that is unique across the whole list, like an id. Then check the data for repeated values.

Where it comes from

@markless/web raises this code. Source:

• packages/web/src/fns/direct.ts
• packages/web/src/fns/repeats.ts
• packages/web/src/repeat-runtime.ts
• packages/web/src/resume-keyed-repeats.ts

Read how to read a Markless error, or go back to all error codes.