nl_tokens: Optimizes tree node : replaces empty nodes with their children
pl_tokens: function squash ( node ) { for ( var i = node . children . length - 1 ; i >= 0 ; i -- ) { /** @type AbbreviationNode */ var n = node . children [ i ] ; if ( n . isGroup ( ) ) { n . replace ( squash ( n ) . children ) ; } else if ( n . isEmpty ( ) ) { n . remove ( ) ; } } _ . each ( node . children , squash ) ; return <mask> ; }