Function hasArrayNature

docs/lib/react.js:18391–18411

* Perform a heuristic test to determine if an object is "array-like". * * A monk asked Joshu, a Zen master, "Has a dog Buddha nature?" * Joshu replied: "Mu." * * This function determines if its argument has "array nature": it returns * true if the argument is an actual array, an `arguments

(obj)

 * @return {boolean}
 */
function hasArrayNature(obj) {
  return(
    // not null/false
    !!obj && (
    // arrays are objects, NodeLists are functions in Safari
    typeof obj == 'object' || typeof obj == 'function') &&
    // quacks like an array
    'length' in obj &&
    // not window
    !('setInterval' in obj) &&
    // no DOM node should be considered an array-like
    // a 'select' element has 'length' and 'item' properties on IE8
    typeof obj.nodeType != 'number' && (
    // a real array
    Array.isArray(obj) ||
    // arguments
    'callee' in obj ||
    // HTMLCollection/NodeList
    'item' in obj)
  );
}

/**
 * Ensure that the argument is an array by wrapping it in an array if it is not.