@dillonkearns/elm-graphql/examples/src/subscription/node_modules/es5-ext/object/is-plain-function.js

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"use strict";

var isClassStr = RegExp.prototype.test.bind(/^\s*class[\s{/}]/)
  , fnToString = Function.prototype.toString;

module.exports = function (fn) {
	if (typeof fn !== "function") return false;
	if (typeof fn.call !== "function") return false;
	if (typeof fn.apply !== "function") return false;
	return !isClassStr(fnToString.call(fn));
};