nl_tokens: Detects the value of an option at the tree node .
pl_tokens: function ( ast ) { let detected = [ ] ; ast . traverse ( function ( node , index , parent ) { // If we see a zero with unit and it is not degree, // then we don’t have an option if ( node . is ( 'percentage' ) && node . first ( 'number' ) . content [ 1 ] === '0' ) { detected . push ( false ) ; return ; } if ( node . is ( 'dimension' ) && node . first ( 'number' ) . content === '0' && node . first ( 'ident' ) . content !== 'deg' ) { detected . push ( false ) ; return ; } // If we see a zero and previous node is not percentage // or dimension, then we have an option if ( node . is ( 'number' ) && node . content === '0' && ! parent . is ( 'percentage' ) && ! <mask> . is ( 'dimension' ) ) { detected . push ( true ) ; } } ) ; return detected ; }