if A has a value to choose A, if B has a value to choose B, neither has a value to choose C. how to write
/ / Please paste the code text below (do not replace the code with pictures)
do not know what type of value ABC is. If it is the original type, as long as it is judged to be non-empty, the fastest value is short circuit or
.A||B||Cif it is an object type, or if the judgment is complicated
A!==null?A:(B!==null?B:C) //!==null var md,a='',b='',c=3
md = a?a:b?b:c
console.log ('-'+ md)
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