_methodFingerprint.js
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define(['exports', './_getLength', './isFunction', './allKeys'], function (exports, _getLength, isFunction, allKeys) {
// Since the regular `Object.prototype.toString` type tests don't work for
// some types in IE 11, we use a fingerprinting heuristic instead, based
// on the methods. It's not great, but it's the best we got.
// The fingerprint method lists are defined below.
function ie11fingerprint(methods) {
var length = _getLength(methods);
return function(obj) {
if (obj == null) return false;
// `Map`, `WeakMap` and `Set` have no enumerable keys.
var keys = allKeys(obj);
if (_getLength(keys)) return false;
for (var i = 0; i < length; i++) {
if (!isFunction(obj[methods[i]])) return false;
}
// If we are testing against `WeakMap`, we need to ensure that
// `obj` doesn't have a `forEach` method in order to distinguish
// it from a regular `Map`.
return methods !== weakMapMethods || !isFunction(obj[forEachName]);
};
}
// In the interest of compact minification, we write
// each string in the fingerprints only once.
var forEachName = 'forEach',
hasName = 'has',
commonInit = ['clear', 'delete'],
mapTail = ['get', hasName, 'set'];
// `Map`, `WeakMap` and `Set` each have slightly different
// combinations of the above sublists.
var mapMethods = commonInit.concat(forEachName, mapTail),
weakMapMethods = commonInit.concat(mapTail),
setMethods = ['add'].concat(commonInit, forEachName, hasName);
exports.ie11fingerprint = ie11fingerprint;
exports.mapMethods = mapMethods;
exports.setMethods = setMethods;
exports.weakMapMethods = weakMapMethods;
Object.defineProperty(exports, '__esModule', { value: true });
});