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node_modules/core-js/internals/composite-key.js

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+'use strict';
+// TODO: in core-js@4, move /modules/ dependencies to public entries for better optimization by tools like `preset-env`
+require('../modules/es.map');
+require('../modules/es.weak-map');
+var getBuiltIn = require('../internals/get-built-in');
+var create = require('../internals/object-create');
+var isObject = require('../internals/is-object');
+
+var $Object = Object;
+var $TypeError = TypeError;
+var Map = getBuiltIn('Map');
+var WeakMap = getBuiltIn('WeakMap');
+
+var Node = function () {
+  // keys
+  this.object = null;
+  this.symbol = null;
+  // child nodes
+  this.primitives = null;
+  this.objectsByIndex = create(null);
+};
+
+Node.prototype.get = function (key, initializer) {
+  return this[key] || (this[key] = initializer());
+};
+
+Node.prototype.next = function (i, it, IS_OBJECT) {
+  var store = IS_OBJECT
+    ? this.objectsByIndex[i] || (this.objectsByIndex[i] = new WeakMap())
+    : this.primitives || (this.primitives = new Map());
+  var entry = store.get(it);
+  if (!entry) store.set(it, entry = new Node());
+  return entry;
+};
+
+var root = new Node();
+
+module.exports = function () {
+  var active = root;
+  var length = arguments.length;
+  var i, it;
+  // for prevent leaking, start from objects
+  for (i = 0; i < length; i++) {
+    if (isObject(it = arguments[i])) active = active.next(i, it, true);
+  }
+  if (this === $Object && active === root) throw $TypeError('Composite keys must contain a non-primitive component');
+  for (i = 0; i < length; i++) {
+    if (!isObject(it = arguments[i])) active = active.next(i, it, false);
+  } return active;
+};