nl_tokens: Merge a single property
pl_tokens: function mergeProperty ( destination , source , property ) { if ( source [ property ] instanceof Array ) { mergeAsArray ( destination , source , property ) ; } else if ( isPrimitive ( source [ property ] ) || ! isLiteral ( source [ property ] ) ) { overrideIfNotExists ( destination , source , <mask> ) ; } else { mergeAsObject ( destination , source , property ) ; } }