index.js
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'use strict';
var fnToStr = Function.prototype.toString;
var reflectApply = typeof Reflect === 'object' && Reflect !== null && Reflect.apply;
var badArrayLike;
var isCallableMarker;
if (typeof reflectApply === 'function' && typeof Object.defineProperty === 'function') {
try {
badArrayLike = Object.defineProperty({}, 'length', {
get: function () {
throw isCallableMarker;
}
});
isCallableMarker = {};
// eslint-disable-next-line no-throw-literal
reflectApply(function () { throw 42; }, null, badArrayLike);
} catch (_) {
if (_ !== isCallableMarker) {
reflectApply = null;
}
}
} else {
reflectApply = null;
}
var constructorRegex = /^\s*class\b/;
var isES6ClassFn = function isES6ClassFunction(value) {
try {
var fnStr = fnToStr.call(value);
return constructorRegex.test(fnStr);
} catch (e) {
return false; // not a function
}
};
var tryFunctionObject = function tryFunctionToStr(value) {
try {
if (isES6ClassFn(value)) { return false; }
fnToStr.call(value);
return true;
} catch (e) {
return false;
}
};
var toStr = Object.prototype.toString;
var objectClass = '[object Object]';
var fnClass = '[object Function]';
var genClass = '[object GeneratorFunction]';
var ddaClass = '[object HTMLAllCollection]'; // IE 11
var ddaClass2 = '[object HTML document.all class]';
var ddaClass3 = '[object HTMLCollection]'; // IE 9-10
var hasToStringTag = typeof Symbol === 'function' && !!Symbol.toStringTag; // better: use `has-tostringtag`
var isIE68 = !(0 in [,]); // eslint-disable-line no-sparse-arrays, comma-spacing
var isDDA = function isDocumentDotAll() { return false; };
if (typeof document === 'object') {
// Firefox 3 canonicalizes DDA to undefined when it's not accessed directly
var all = document.all;
if (toStr.call(all) === toStr.call(document.all)) {
isDDA = function isDocumentDotAll(value) {
/* globals document: false */
// in IE 6-8, typeof document.all is "object" and it's truthy
if ((isIE68 || !value) && (typeof value === 'undefined' || typeof value === 'object')) {
try {
var str = toStr.call(value);
return (
str === ddaClass
|| str === ddaClass2
|| str === ddaClass3 // opera 12.16
|| str === objectClass // IE 6-8
) && value('') == null; // eslint-disable-line eqeqeq
} catch (e) { /**/ }
}
return false;
};
}
}
module.exports = reflectApply
? function isCallable(value) {
if (isDDA(value)) { return true; }
if (!value) { return false; }
if (typeof value !== 'function' && typeof value !== 'object') { return false; }
try {
reflectApply(value, null, badArrayLike);
} catch (e) {
if (e !== isCallableMarker) { return false; }
}
return !isES6ClassFn(value) && tryFunctionObject(value);
}
: function isCallable(value) {
if (isDDA(value)) { return true; }
if (!value) { return false; }
if (typeof value !== 'function' && typeof value !== 'object') { return false; }
if (hasToStringTag) { return tryFunctionObject(value); }
if (isES6ClassFn(value)) { return false; }
var strClass = toStr.call(value);
if (strClass !== fnClass && strClass !== genClass && !(/^\[object HTML/).test(strClass)) { return false; }
return tryFunctionObject(value);
};