Function globPatternToRegex

packages/kaos/src/internal.ts:186–238

(pattern: string, caseSensitive: boolean)

 * @internal
 */
export function globPatternToRegex(pattern: string, caseSensitive: boolean): RegExp {
  let regex = '^';
  for (let i = 0; i < pattern.length; i++) {
    const ch = pattern[i];
    if (ch === undefined) break;
    switch (ch) {
      case '*':
        regex += '[^/]*';
        break;
      case '?':
        regex += '[^/]';
        break;
      case '[': {
        const end = pattern.indexOf(']', i + 1);
        if (end === -1) {
          regex += '\\[';
        } else {
          // Glob character classes only use `!` for negation. A literal
          // leading `^` must remain literal even though JS regex char
          // classes treat it as negation in the first position.
          let charClass = pattern.slice(i + 1, end);
          // Escape backslashes inside the class so a trailing backslash
          // does not accidentally escape the closing `]`.
          charClass = charClass.replace(/\\/g, '\\\\');
          if (charClass.startsWith('!')) {
            charClass = '^' + charClass.slice(1);
          } else if (charClass.startsWith('^')) {
            charClass = '\\' + charClass;
          }
          regex += '[' + charClass + ']';
          i = end;
        }
        break;
      }
      case '\\': {
        if (i + 1 < pattern.length) {
          const next = pattern.charAt(i + 1);
          regex += next.replaceAll(/[{}()+.\\[\]^$|]/g, '\\$&');
          // Advance past the escaped character so it is not processed
          // again as a regex metacharacter. match literally.
          i++;
        } else {
          regex += '\\\\';
        }
        break;
      }
      default:
        regex += ch.replaceAll(/[{}()+.\\[\]^$|]/g, '\\$&');
    }
  }
  regex += '$';
  return new RegExp(regex, caseSensitive ? '' : 'i');
}

/**
 * A Readable wrapper that preserves source backpressure while still allowing