import getLength from './_getLength.js';
import isFunction from './isFunction.js';
import allKeys from './allKeys.js';import getLength from './_getLength.js';
import isFunction from './isFunction.js';
import allKeys from './allKeys.js';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.
export 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.
export var mapMethods = commonInit.concat(forEachName, mapTail),
weakMapMethods = commonInit.concat(mapTail),
setMethods = ['add'].concat(commonInit, forEachName, hasName);