fix: address ambiguity between nargs of 1 and requiresArg #1572
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In #1054,
requiresArg
was refactored to use anargs
of1
to specify that a value was required following an option (--x foo
is valid,--x
is not valid).The problem with this design decision was that it created an ambiguity when
array
andnargs
were used in conjunction, one could not distinguish between:This behavior lead to issues like #1570, #1098, and mochajs/mocha#4196.
To solve this problem
nargs
now accepts the special valueNaN
, this value is used byrequiresArg
to specify that anarray
accepts "one or more" values following it. Anargs
of1
used in conjunction witharray
, continues to indicate that just one value should be accepted by an array.