nl_tokens: Returns a symmetrically padded domain for polar charts
pl_tokens: function getSymmetricDomain ( domain , values ) { const processedData = sortedUniq ( <mask> . sort ( ( a , b ) => a - b ) ) ; const step = processedData [ 1 ] - processedData [ 0 ] ; return [ domain [ 0 ] , domain [ 1 ] + step ] ; }