- isZeroLength(element, flags): boolean
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Parameters
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element: Alternative | CapturingGroup | ClassRangesCharacterClass | UnicodeSetsCharacterClass | CharacterClassRange | ClassIntersection | ClassStringDisjunction | ClassSubtraction | ExpressionCharacterClass | Group | LookaheadAssertion | LookbehindAssertion | Quantifier | StringAlternative | Backreference | EdgeAssertion | WordBoundaryAssertion | Character | AnyCharacterSet | EscapeCharacterSet | CharacterUnicodePropertyCharacterSet | StringsUnicodePropertyCharacterSet | readonly Alternative[]
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Returns boolean
Returns whether all (but at least one of the) paths of the given element do not consume characters.
If this function returns
true, then isPotentiallyZeroLength is guaranteed to returntrue.Backreferences
This function uses the same condition for backreferences as isEmpty.
Relations
isZeroLength(e) -> isPotentiallyZeroLength(e)isZeroLength(e) -> getLengthRange(e).max == 0