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 isConstructor(argument) { if (!isCallable(argument)) return false; try { construct(noop, empty, argument); return true; } catch (error) { return false; } }; var isConstructorLegacy = function isConstructor(argument) { if (!isCallable(argument)) return false; switch (classof(argument)) { case 'AsyncFunction': case 'GeneratorFunction': case 'AsyncGeneratorFunction': return false; } try { // we can't check .prototype since constructors produced by .bind haven't it // `Function#toString` throws on some built-it function in some legacy engines // (for example, `DOMQuad` and similar in FF41-) return INCORRECT_TO_STRING || !!exec(constructorRegExp, inspectSource(argument)); } catch (error) { return true; } }; isConstructorLegacy.sham = true; // `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;