Function lex

lib/preloadjs-NEXT.js:1570–1725

()

        // the end of the source string. A token may be a string, number, `null`
        // literal, or Boolean literal.
        var lex = function () {
          var source = Source, length = source.length, value, begin, position, isSigned, charCode;
          while (Index < length) {
            charCode = source.charCodeAt(Index);
            switch (charCode) {
              case 9: case 10: case 13: case 32:
                // Skip whitespace tokens, including tabs, carriage returns, line
                // feeds, and space characters.
                Index++;
                break;
              case 123: case 125: case 91: case 93: case 58: case 44:
                // Parse a punctuator token (`{`, `}`, `[`, `]`, `:`, or `,`) at
                // the current position.
                value = charIndexBuggy ? source.charAt(Index) : source[Index];
                Index++;
                return value;
              case 34:
                // `"` delimits a JSON string; advance to the next character and
                // begin parsing the string. String tokens are prefixed with the
                // sentinel `@` character to distinguish them from punctuators and
                // end-of-string tokens.
                for (value = "@", Index++; Index < length;) {
                  charCode = source.charCodeAt(Index);
                  if (charCode < 32) {
                    // Unescaped ASCII control characters (those with a code unit
                    // less than the space character) are not permitted.
                    abort();
                  } else if (charCode == 92) {
                    // A reverse solidus (`\`) marks the beginning of an escaped
                    // control character (including `"`, `\`, and `/`) or Unicode
                    // escape sequence.
                    charCode = source.charCodeAt(++Index);
                    switch (charCode) {
                      case 92: case 34: case 47: case 98: case 116: case 110: case 102: case 114:
                        // Revive escaped control characters.
                        value += Unescapes[charCode];
                        Index++;
                        break;
                      case 117:
                        // `\u` marks the beginning of a Unicode escape sequence.
                        // Advance to the first character and validate the
                        // four-digit code point.
                        begin = ++Index;
                        for (position = Index + 4; Index < position; Index++) {
                          charCode = source.charCodeAt(Index);
                          // A valid sequence comprises four hexdigits (case-
                          // insensitive) that form a single hexadecimal value.
                          if (!(charCode >= 48 && charCode <= 57 || charCode >= 97 && charCode <= 102 || charCode >= 65 && charCode <= 70)) {
                            // Invalid Unicode escape sequence.
                            abort();
                          }
                        }
                        // Revive the escaped character.
                        value += fromCharCode("0x" + source.slice(begin, Index));
                        break;
                      default:
                        // Invalid escape sequence.
                        abort();