const REGEX_SPECIAL = /[\\^$.*+?()[\]{}|]/g
const REGEX_HAS_SPECIAL = RegExp(REGEX_SPECIAL.source)
function toSource(source) {
source = Array.isArray(source) ? source : [source]
source = source.map((item) => (item instanceof RegExp ? item.source : item))
return source.join('')
}
export function pattern(source) {
return new RegExp(toSource(source), 'g')
}
export function withoutCapturing(source) {
return new RegExp(`(?:${toSource(source)})`, 'g')
}
export function any(sources) {
return `(?:${sources.map(toSource).join('|')})`
}
export function optional(source) {
return `(?:${toSource(source)})?`
}
export function zeroOrMore(source) {
return `(?:${toSource(source)})*`
}
export function nestedBrackets(open, close, depth = 1) {
return withoutCapturing([
escape(open),
/[^\s]*/,
depth === 1
? `[^${escape(open)}${escape(close)}\s]*`
: any([`[^${escape(open)}${escape(close)}\s]*`, nestedBrackets(open, close, depth - 1)]),
/[^\s]*/,
escape(close),
])
}
export function escape(string) {
return string && REGEX_HAS_SPECIAL.test(string)
? string.replace(REGEX_SPECIAL, '\\$&')
: string || ''
}