Function removeMarkedSpan

static/editor.md/lib/codemirror/lib/codemirror.js:6120–6124

(spans, span)

  // Remove a span from an array, returning undefined if no spans are
  // left (we don't store arrays for lines without spans).
  function removeMarkedSpan(spans, span) {
    for (var r, i = 0; i < spans.length; ++i)
      if (spans[i] != span) (r || (r = [])).push(spans[i]);
    return r;
  }
  // Add a span to a line.
  function addMarkedSpan(line, span) {
    line.markedSpans = line.markedSpans ? line.markedSpans.concat([span]) : [span];