bigint-crypto-utils/node_modules/is-callable/index.js

38 lines
1.1 KiB
JavaScript

'use strict';
var fnToStr = Function.prototype.toString;
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 fnClass = '[object Function]';
var genClass = '[object GeneratorFunction]';
var hasToStringTag = typeof Symbol === 'function' && typeof Symbol.toStringTag === 'symbol';
module.exports = function isCallable(value) {
if (!value) { return false; }
if (typeof value !== 'function' && typeof value !== 'object') { return false; }
if (typeof value === 'function' && !value.prototype) { return true; }
if (hasToStringTag) { return tryFunctionObject(value); }
if (isES6ClassFn(value)) { return false; }
var strClass = toStr.call(value);
return strClass === fnClass || strClass === genClass;
};