nl_tokens: Maximally minimal classes http : // wiki . ecmascript . org / doku . php?id = strawman : maximally_minimal_classes This transforms class declarations and class expressions . class C extends B { constructor ( x ) { super () ; } method () { super . m () ; } } = > var C = function ( x ) { $__superCall ( this $C . prototype constructor [] ) ; } ; var $C = $traceurRuntime . createClass ( C { method : function () { $traceurRuntime . superCall ( this $C . prototype m [] ) ; } } {} B ) ;
pl_tokens: function classCall ( func , object , staticObject , superClass ) { if ( superClass ) { return parseExpression ` ${ func } ${ object } ${ staticObject } ${ superClass } ` ; } return parseExpression ` ${ func } ${ <mask> } ${ staticObject } ` ; }