--- /dev/null
+var uncurryThis = require('../internals/function-uncurry-this');
+var fails = require('../internals/fails');
+var isCallable = require('../internals/is-callable');
+var classof = require('../internals/classof');
+var getBuiltIn = require('../internals/get-built-in');
+var inspectSource = require('../internals/inspect-source');
+
+var noop = function () { /* empty */ };
+var empty = [];
+var construct = getBuiltIn('Reflect', 'construct');
+var constructorRegExp = /^\s*(?:class|function)\b/;
+var exec = uncurryThis(constructorRegExp.exec);
+var INCORRECT_TO_STRING = !constructorRegExp.exec(noop);
+
+var isConstructorModern = function (argument) {
+ if (!isCallable(argument)) return false;
+ try {
+ construct(noop, empty, argument);
+ return true;
+ } catch (error) {
+ return false;
+ }
+};
+
+var isConstructorLegacy = function (argument) {
+ if (!isCallable(argument)) return false;
+ switch (classof(argument)) {
+ case 'AsyncFunction':
+ case 'GeneratorFunction':
+ case 'AsyncGeneratorFunction': return false;
+ // we can't check .prototype since constructors produced by .bind haven't it
+ } return INCORRECT_TO_STRING || !!exec(constructorRegExp, inspectSource(argument));
+};
+
+// `IsConstructor` abstract operation
+// https://tc39.es/ecma262/#sec-isconstructor
+module.exports = !construct || fails(function () {
+ var called;
+ return isConstructorModern(isConstructorModern.call)
+ || !isConstructorModern(Object)
+ || !isConstructorModern(function () { called = true; })
+ || called;
+}) ? isConstructorLegacy : isConstructorModern;