Function getLongestPrefix

getLongestPrefix(alternative, direction, flags, options?): readonly CharSet[]
Returns the longest knowable prefix guaranteed to always be accepted by the given alternative (ignoring assertions).

All character sets except the last one are guaranteed to be non-empty. The last character set is only guaranteed to be non-empty if includeAfter: false.
Parameters
- alternative: Alternative
- direction: MatchingDirection
- flags: ReadonlyFlags
- options: Readonly<GetLongestPrefixOptions> = {}
Returns readonly CharSet[]