nl_tokens: Returns a copy of the input in which any property that hasn t explicitly been expressed in the schema is stripped .
pl_tokens: function mapPrune ( <mask> , schema ) { var result = { } ; _ . forOwn ( schema , function ( value , key ) { if ( _ . isPlainObject ( value ) ) { // Recursive. result [ key ] = mapPrune ( input [ key ] || { } , value ) ; } else { // Base. Null is set as the default value. result [ key ] = input [ key ] || null ; } } ) ; return result ; }