nl_tokens: Warns if there is a duplicate or missing key
pl_tokens: function warnOnInvalidKey ( <mask> , knownKeys ) { { if ( typeof child !== 'object' || child === null ) { return knownKeys ; } switch ( child . $$typeof ) { case REACT_ELEMENT_TYPE : case REACT_PORTAL_TYPE : warnForMissingKey ( child ) ; var key = child . key ; if ( typeof key !== 'string' ) { break ; } if ( knownKeys === null ) { knownKeys = new Set ( ) ; knownKeys . add ( key ) ; break ; } if ( ! knownKeys . has ( key ) ) { knownKeys . add ( key ) ; break ; } warning$1 ( false , 'Encountered two children with the same key, `%s`. ' + 'Keys should be unique so that components maintain their identity ' + 'across updates. Non-unique keys may cause children to be ' + 'duplicated and/or omitted — the behavior is unsupported and ' + ' ould change in a future version.',  k y); break ; default : break ; } } return knownKeys ; }