Function lookahead

frontend/public/swagger-ui-bundle.js:7165–7167

(s)

            return s ? ('string' == typeof s ? s : s.source) : null
          }
          function lookahead(s) {
            return concat('(?=', s, ')')
          }
          function concat(...s) {
            return s.map((s) => source(s)).join('')
          }