Notes/libraries/codemirror/mode/jsx/jsx.js

// CodeMirror, copyright (c) by Marijn Haverbeke and others
// Distributed under an MIT license: https://codemirror.net/LICENSE

(function(mod) {
  if (typeof exports == "object" && typeof module == "object") // CommonJS
    mod(require("../../lib/codemirror"), require("../xml/xml"), require("../javascript/javascript"))
  else if (typeof define == "function" && define.amd) // AMD
    define(["../../lib/codemirror", "../xml/xml", "../javascript/javascript"], mod)
  else // Plain browser env
    mod(CodeMirror)
})(function(CodeMirror) {
  "use strict"

  // Depth means the amount of open braces in JS context, in XML
  // context 0 means not in tag, 1 means in tag, and 2 means in tag
  // and js block comment.
  function Context(state, mode, depth, prev) {
    this.state = state; this.mode = mode; this.depth = depth; this.prev = prev
  }

  function copyContext(context) {
    return new Context(CodeMirror.copyState(context.mode, context.state),
                       context.mode,
                       context.depth,
                       context.prev && copyContext(context.prev))
  }

  CodeMirror.defineMode("jsx", function(config, modeConfig) {
    var xmlMode = CodeMirror.getMode(config, {name: "xml", allowMissing: true, multilineTagIndentPastTag: false, allowMissingTagName: true})
    var jsMode = CodeMirror.getMode(config, modeConfig && modeConfig.base || "javascript")

    function flatXMLIndent(state) {
      var tagName = state.tagName
      state.tagName = null
      var result = xmlMode.indent(state, "", "")
      state.tagName = tagName
      return result
    }

    function token(stream, state) {
      if (state.context.mode == xmlMode)
        return xmlToken(stream, state, state.context)
      else
        return jsToken(stream, state, state.context)
    }

    function xmlToken(stream, state, cx) {
      if (cx.depth == 2) { // Inside a JS /* */ comment
        if (stream.match(/^.*?\*\//)) cx.depth = 1
        else stream.skipToEnd()
        return "comment"
      }

      if (stream.peek() == "{") {
        xmlMode.skipAttribute(cx.state)

        var indent = flatXMLIndent(cx.state), xmlContext = cx.state.context
        // If JS starts on same line as tag
        if (xmlContext && stream.match(/^[^>]*>\s*$/, false)) {
          while (xmlContext.prev && !xmlContext.startOfLine)
            xmlContext = xmlContext.prev
          // If tag starts the line, use XML indentation level
          if (xmlContext.startOfLine) indent -= config.indentUnit
          // Else use JS indentation level
          else if (cx.prev.state.lexical) indent = cx.prev.state.lexical.indented
        // Else if inside of tag
        } else if (cx.depth == 1) {
          indent += config.indentUnit
        }

        state.context = new Context(CodeMirror.startState(jsMode, indent),
                                    jsMode, 0, state.context)
        return null
      }

      if (cx.depth == 1) { // Inside of tag
        if (stream.peek() == "<") { // Tag inside of tag
          xmlMode.skipAttribute(cx.state)
          state.context = new Context(CodeMirror.startState(xmlMode, flatXMLIndent(cx.state)),
                                      xmlMode, 0, state.context)
          return null
        } else if (stream.match("//")) {
          stream.skipToEnd()
          return "comment"
        } else if (stream.match("/*")) {
          cx.depth = 2
          return token(stream, state)
        }
      }

      var style = xmlMode.token(stream, cx.state), cur = stream.current(), stop
      if (/\btag\b/.test(style)) {
        if (/>$/.test(cur)) {
          if (cx.state.context) cx.depth = 0
          else state.context = state.context.prev
        } else if (/^</.test(cur)) {
          cx.depth = 1
        }
      } else if (!style && (stop = cur.indexOf("{")) > -1) {
        stream.backUp(cur.length - stop)
      }
      return style
    }

    function jsToken(stream, state, cx) {
      if (stream.peek() == "<" && jsMode.expressionAllowed(stream, cx.state)) {
        jsMode.skipExpression(cx.state)
        state.context = new Context(CodeMirror.startState(xmlMode, jsMode.indent(cx.state, "", "")),
                                    xmlMode, 0, state.context)
        return null
      }

      var style = jsMode.token(stream, cx.state)
      if (!style && cx.depth != null) {
        var cur = stream.current()
        if (cur == "{") {
          cx.depth++
        } else if (cur == "}") {
          if (--cx.depth == 0) state.context = state.context.prev
        }
      }
      return style
    }

    return {
      startState: function() {
        return {context: new Context(CodeMirror.startState(jsMode), jsMode)}
      },

      copyState: function(state) {
        return {context: copyContext(state.context)}
      },

      token: token,

      indent: function(state, textAfter, fullLine) {
        return state.context.mode.indent(state.context.state, textAfter, fullLine)
      },

      innerMode: function(state) {
        return state.context
      }
    }
  }, "xml", "javascript")

  CodeMirror.defineMIME("text/jsx", "jsx")
  CodeMirror.defineMIME("text/typescript-jsx", {name: "jsx", base: {name: "javascript", typescript: true}})
});