Strictly checking for  === null, rather than ambiguous false
Strictly checking for  === null, rather than ambiguous false

kkiernan/commonmark,kkiernan/commonmark,garethellis36/commonmark,hason/commonmark,fesor/commonmark,colinodell/commonmark,thephpleague/commonmark,postalservice14/commonmark,fesor/commonmark,postalservice14/commonmark,thephpleague/commonmark,stof/commonmark,bcremer/commonmark,garethellis36/commonmark,hason/commonmark