Function extendSelections

static/editor.md/lib/codemirror/lib/codemirror.js:2045–2050

(doc, heads, options)

  // Extend all selections (pos is an array of selections with length
  // equal the number of selections)
  function extendSelections(doc, heads, options) {
    for (var out = [], i = 0; i < doc.sel.ranges.length; i++)
      out[i] = extendRange(doc, doc.sel.ranges[i], heads[i], null);
    var newSel = normalizeSelection(out, doc.sel.primIndex);
    setSelection(doc, newSel, options);
  }

  // Updates a single range in the selection.
  function replaceOneSelection(doc, i, range, options) {