function parseTemplate()

in static/js/mustache.js [115:255]

• 85 lines of code
• 24 McCabe index (conditional complexity)

  function parseTemplate (template, tags) {
    if (!template)
      return [];
    var lineHasNonSpace = false;
    var sections = [];     // Stack to hold section tokens
    var tokens = [];       // Buffer to hold the tokens
    var spaces = [];       // Indices of whitespace tokens on the current line
    var hasTag = false;    // Is there a {{tag}} on the current line?
    var nonSpace = false;  // Is there a non-space char on the current line?
    var indentation = '';  // Tracks indentation for tags that use it
    var tagIndex = 0;      // Stores a count of number of tags encountered on a line

    // Strips all whitespace tokens array for the current line
    // if there was a {{#tag}} on it and otherwise only space.
    function stripSpace () {
      if (hasTag && !nonSpace) {
        while (spaces.length)
          delete tokens[spaces.pop()];
      } else {
        spaces = [];
      }

      hasTag = false;
      nonSpace = false;
    }

    var openingTagRe, closingTagRe, closingCurlyRe;
    function compileTags (tagsToCompile) {
      if (typeof tagsToCompile === 'string')
        tagsToCompile = tagsToCompile.split(spaceRe, 2);

      if (!isArray(tagsToCompile) || tagsToCompile.length !== 2)
        throw new Error('Invalid tags: ' + tagsToCompile);

      openingTagRe = new RegExp(escapeRegExp(tagsToCompile[0]) + '\\s*');
      closingTagRe = new RegExp('\\s*' + escapeRegExp(tagsToCompile[1]));
      closingCurlyRe = new RegExp('\\s*' + escapeRegExp('}' + tagsToCompile[1]));
    }

    compileTags(tags || mustache.tags);

    var scanner = new Scanner(template);

    var start, type, value, chr, token, openSection;
    while (!scanner.eos()) {
      start = scanner.pos;

      // Match any text between tags.
      value = scanner.scanUntil(openingTagRe);

      if (value) {
        for (var i = 0, valueLength = value.length; i < valueLength; ++i) {
          chr = value.charAt(i);

          if (isWhitespace(chr)) {
            spaces.push(tokens.length);
            indentation += chr;
          } else {
            nonSpace = true;
            lineHasNonSpace = true;
            indentation += ' ';
          }

          tokens.push([ 'text', chr, start, start + 1 ]);
          start += 1;

          // Check for whitespace on the current line.
          if (chr === '\n') {
            stripSpace();
            indentation = '';
            tagIndex = 0;
            lineHasNonSpace = false;
          }
        }
      }

      // Match the opening tag.
      if (!scanner.scan(openingTagRe))
        break;

      hasTag = true;

      // Get the tag type.
      type = scanner.scan(tagRe) || 'name';
      scanner.scan(whiteRe);

      // Get the tag value.
      if (type === '=') {
        value = scanner.scanUntil(equalsRe);
        scanner.scan(equalsRe);
        scanner.scanUntil(closingTagRe);
      } else if (type === '{') {
        value = scanner.scanUntil(closingCurlyRe);
        scanner.scan(curlyRe);
        scanner.scanUntil(closingTagRe);
        type = '&';
      } else {
        value = scanner.scanUntil(closingTagRe);
      }

      // Match the closing tag.
      if (!scanner.scan(closingTagRe))
        throw new Error('Unclosed tag at ' + scanner.pos);

      if (type == '>') {
        token = [ type, value, start, scanner.pos, indentation, tagIndex, lineHasNonSpace ];
      } else {
        token = [ type, value, start, scanner.pos ];
      }
      tagIndex++;
      tokens.push(token);

      if (type === '#' || type === '^') {
        sections.push(token);
      } else if (type === '/') {
        // Check section nesting.
        openSection = sections.pop();

        if (!openSection)
          throw new Error('Unopened section "' + value + '" at ' + start);

        if (openSection[1] !== value)
          throw new Error('Unclosed section "' + openSection[1] + '" at ' + start);
      } else if (type === 'name' || type === '{' || type === '&') {
        nonSpace = true;
      } else if (type === '=') {
        // Set the tags for the next time around.
        compileTags(value);
      }
    }

    stripSpace();

    // Make sure there are no open sections when we're done.
    openSection = sections.pop();

    if (openSection)
      throw new Error('Unclosed section "' + openSection[1] + '" at ' + scanner.pos);

    return nestTokens(squashTokens(tokens));
  }