Function indexOf

static/editor.md/lib/codemirror/lib/codemirror.js:8073–8077

(array, elt)

    selectInput = function(node) { try { node.select(); } catch(_e) {} };

  function indexOf(array, elt) {
    for (var i = 0; i < array.length; ++i)
      if (array[i] == elt) return i;
    return -1;
  }
  function map(array, f) {
    var out = [];
    for (var i = 0; i < array.length; i++) out[i] = f(array[i], i);