first

node_modules/core-js/modules/esnext.map.reduce.js

@@ -0,0 +1,28 @@
+'use strict';
+var $ = require('../internals/export');
+var aCallable = require('../internals/a-callable');
+var aMap = require('../internals/a-map');
+var iterate = require('../internals/map-iterate');
+
+var $TypeError = TypeError;
+
+// `Map.prototype.reduce` method
+// https://github.com/tc39/proposal-collection-methods
+$({ target: 'Map', proto: true, real: true, forced: true }, {
+  reduce: function reduce(callbackfn /* , initialValue */) {
+    var map = aMap(this);
+    var noInitial = arguments.length < 2;
+    var accumulator = noInitial ? undefined : arguments[1];
+    aCallable(callbackfn);
+    iterate(map, function (value, key) {
+      if (noInitial) {
+        noInitial = false;
+        accumulator = value;
+      } else {
+        accumulator = callbackfn(accumulator, value, key, map);
+      }
+    });
+    if (noInitial) throw $TypeError('Reduce of empty map with no initial value');
+    return accumulator;
+  }
+});