main repo

node_modules/is-async-function/index.js

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+'use strict';
+
+var toStr = Object.prototype.toString;
+var fnToStr = Function.prototype.toString;
+var isFnRegex = /^\s*async(?:\s+function(?:\s+|\()|\s*\()/;
+var hasToStringTag = require('has-tostringtag/shams')();
+var getProto = Object.getPrototypeOf;
+var getAsyncFunc = function () { // eslint-disable-line consistent-return
+	if (!hasToStringTag) {
+		return false;
+	}
+	try {
+		return Function('return async function () {}')();
+	} catch (e) {
+	}
+};
+var AsyncFunction;
+
+module.exports = function isAsyncFunction(fn) {
+	if (typeof fn !== 'function') {
+		return false;
+	}
+	if (isFnRegex.test(fnToStr.call(fn))) {
+		return true;
+	}
+	if (!hasToStringTag) {
+		var str = toStr.call(fn);
+		return str === '[object AsyncFunction]';
+	}
+	if (!getProto) {
+		return false;
+	}
+	if (typeof AsyncFunction === 'undefined') {
+		var asyncFunc = getAsyncFunc();
+		AsyncFunction = asyncFunc ? getProto(asyncFunc) : false;
+	}
+	return getProto(fn) === AsyncFunction;
+};