vue源码分析day1-ast实现.md

源码分析

parseHTML主要对html进行截取，匹配，分析，然后调用传入的options中的处理函数，在父级函数中形成ast结构。

/*
 * 主要的html处理
 */
function parseHTML (html, options) {
  var stack = [];
  var expectHTML = options.expectHTML;
  var isUnaryTag$$1 = options.isUnaryTag || no;
  var canBeLeftOpenTag$$1 = options.canBeLeftOpenTag || no;
  var index = 0;
  var last, lastTag;
  while (html) {
    last = html;
    // Make sure we're not in a plaintext content element like script/style
    // 检测不是script,textarea,style
    if (!lastTag || !isPlainTextElement(lastTag)) {
      var textEnd = html.indexOf('<');
      // 检测<开始的标间
      if (textEnd === 0) {
        // Comment:
        // 处理html 中的注释
        if (comment.test(html)) {
          var commentEnd = html.indexOf('-->');

          if (commentEnd >= 0) {
            if (options.shouldKeepComment) {
              options.comment(html.substring(4, commentEnd));
            }
            advance(commentEnd + 3);
            continue
          }
        }

        // http://en.wikipedia.org/wiki/Conditional_comment#Downlevel-revealed_conditional_comment
        if (conditionalComment.test(html)) {
          var conditionalEnd = html.indexOf(']>');

          if (conditionalEnd >= 0) {
            advance(conditionalEnd + 2);
            continue
          }
        }

        // Doctype:
        var doctypeMatch = html.match(doctype);
        if (doctypeMatch) {
          advance(doctypeMatch[0].length);
          continue
        }

        // End tag:
        // ["

", "div", index: 0, input: "

"] var endTagMatch = html.match(endTag); if (endTagMatch) { var curIndex = index; // 需改index并截取html advance(endTagMatch[0].length); parseEndTag(endTagMatch[1], curIndex, index); continue } // Start tag: //{tagName: "div", attrs: Array(1), start: 23, unarySlash: "", end: 41} /* * 匹配开始到结束，获取属性 */ var startTagMatch = parseStartTag(); if (startTagMatch) { handleStartTag(startTagMatch); if (shouldIgnoreFirstNewline(lastTag, html)) { advance(1); } continue } } var text = (void 0), rest = (void 0), next = (void 0); if (textEnd >= 0) { rest = html.slice(textEnd); while ( !endTag.test(rest) && !startTagOpen.test(rest) && !comment.test(rest) && !conditionalComment.test(rest) ) { // < in plain text, be forgiving and treat it as text next = rest.indexOf('<', 1); if (next < 0) { break } textEnd += next; rest = html.slice(textEnd); } text = html.substring(0, textEnd); advance(textEnd); } if (textEnd < 0) { text = html; html = ''; } if (options.chars && text) { options.chars(text); } } else { var endTagLength = 0; var stackedTag = lastTag.toLowerCase(); var reStackedTag = reCache[stackedTag] || (reCache[stackedTag] = new RegExp('([\\s\\S]*?)( + stackedTag + '[^>]*>)', 'i')); var rest$1 = html.replace(reStackedTag, function (all, text, endTag) { endTagLength = endTag.length; if (!isPlainTextElement(stackedTag) && stackedTag !== 'noscript') { text = text .replace(//g, '$1') .replace(//g, '$1'); } if (shouldIgnoreFirstNewline(stackedTag, text)) { text = text.slice(1); } if (options.chars) { options.chars(text); } return '' }); index += html.length - rest$1.length; html = rest$1; parseEndTag(stackedTag, index - endTagLength, index); } if (html === last) { console.log(html); options.chars && options.chars(html); if ("development" !== 'production' && !stack.length && options.warn) { options.warn(("Mal-formatted tag at end of template: \"" + html + "\"")); } break } } // Clean up any remaining tags parseEndTag(); function advance (n) { index += n; html = html.substring(n); console.log(html); } function parseStartTag () { // ["{{name}}