Unfortunately, the
standard built-in String.prototype.isWellFormed
does a ToString on its input, causing it to judge non-strings to be
well-formed strings if they coerce to a well-formed strings. This
recapitulates the mistake in having the global isNaN coerce its inputs,
causing it to judge non-string to be NaN if they coerce to NaN.
This isWellFormedString function only judges well-formed strings to be
well-formed strings. For all non-strings it returns false.
Is the argument a well-formed string?
Unfortunately, the standard built-in
String.prototype.isWellFormeddoes a ToString on its input, causing it to judge non-strings to be well-formed strings if they coerce to a well-formed strings. This recapitulates the mistake in having the globalisNaNcoerce its inputs, causing it to judge non-string to be NaN if they coerce to NaN.This
isWellFormedStringfunction only judges well-formed strings to be well-formed strings. For all non-strings it returns false.