Function updateDoc

external/.scrollLibs.js:6491–6554

(doc, change, markedSpans, estimateHeight$$1)

  // Perform a change on the document data structure.
  function updateDoc(doc, change, markedSpans, estimateHeight$$1) {
    function spansFor(n) {
      return markedSpans ? markedSpans[n] : null
    }
    function update(line, text, spans) {
      updateLine(line, text, spans, estimateHeight$$1)
      signalLater(line, "change", line, change)
    }
    function linesFor(start, end) {
      var result = []
      for (var i = start; i < end; ++i) {
        result.push(new Line(text[i], spansFor(i), estimateHeight$$1))
      }
      return result
    }

    var from = change.from,
      to = change.to,
      text = change.text
    var firstLine = getLine(doc, from.line),
      lastLine = getLine(doc, to.line)
    var lastText = lst(text),
      lastSpans = spansFor(text.length - 1),
      nlines = to.line - from.line

    // Adjust the line structure
    if (change.full) {
      doc.insert(0, linesFor(0, text.length))
      doc.remove(text.length, doc.size - text.length)
    } else if (isWholeLineUpdate(doc, change)) {
      // This is a whole-line replace. Treated specially to make
      // sure line objects move the way they are supposed to.
      var added = linesFor(0, text.length - 1)
      update(lastLine, lastLine.text, lastSpans)
      if (nlines) {
        doc.remove(from.line, nlines)
      }
      if (added.length) {
        doc.insert(from.line, added)
      }
    } else if (firstLine == lastLine) {
      if (text.length == 1) {
        update(firstLine, firstLine.text.slice(0, from.ch) + lastText + firstLine.text.slice(to.ch), lastSpans)
      } else {
        var added$1 = linesFor(1, text.length - 1)
        added$1.push(new Line(lastText + firstLine.text.slice(to.ch), lastSpans, estimateHeight$$1))
        update(firstLine, firstLine.text.slice(0, from.ch) + text[0], spansFor(0))
        doc.insert(from.line + 1, added$1)
      }
    } else if (text.length == 1) {
      update(firstLine, firstLine.text.slice(0, from.ch) + text[0] + lastLine.text.slice(to.ch), spansFor(0))
      doc.remove(from.line + 1, nlines)
    } else {
      update(firstLine, firstLine.text.slice(0, from.ch) + text[0], spansFor(0))
      update(lastLine, lastText + lastLine.text.slice(to.ch), lastSpans)
      var added$2 = linesFor(1, text.length - 1)
      if (nlines > 1) {
        doc.remove(from.line + 1, nlines - 1)