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node_modules/core-js/internals/internal-metadata.js

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+'use strict';
+var $ = require('../internals/export');
+var uncurryThis = require('../internals/function-uncurry-this');
+var hiddenKeys = require('../internals/hidden-keys');
+var isObject = require('../internals/is-object');
+var hasOwn = require('../internals/has-own-property');
+var defineProperty = require('../internals/object-define-property').f;
+var getOwnPropertyNamesModule = require('../internals/object-get-own-property-names');
+var getOwnPropertyNamesExternalModule = require('../internals/object-get-own-property-names-external');
+var isExtensible = require('../internals/object-is-extensible');
+var uid = require('../internals/uid');
+var FREEZING = require('../internals/freezing');
+
+var REQUIRED = false;
+var METADATA = uid('meta');
+var id = 0;
+
+var setMetadata = function (it) {
+  defineProperty(it, METADATA, { value: {
+    objectID: 'O' + id++, // object ID
+    weakData: {}          // weak collections IDs
+  } });
+};
+
+var fastKey = function (it, create) {
+  // return a primitive with prefix
+  if (!isObject(it)) return typeof it == 'symbol' ? it : (typeof it == 'string' ? 'S' : 'P') + it;
+  if (!hasOwn(it, METADATA)) {
+    // can't set metadata to uncaught frozen object
+    if (!isExtensible(it)) return 'F';
+    // not necessary to add metadata
+    if (!create) return 'E';
+    // add missing metadata
+    setMetadata(it);
+  // return object ID
+  } return it[METADATA].objectID;
+};
+
+var getWeakData = function (it, create) {
+  if (!hasOwn(it, METADATA)) {
+    // can't set metadata to uncaught frozen object
+    if (!isExtensible(it)) return true;
+    // not necessary to add metadata
+    if (!create) return false;
+    // add missing metadata
+    setMetadata(it);
+  // return the store of weak collections IDs
+  } return it[METADATA].weakData;
+};
+
+// add metadata on freeze-family methods calling
+var onFreeze = function (it) {
+  if (FREEZING && REQUIRED && isExtensible(it) && !hasOwn(it, METADATA)) setMetadata(it);
+  return it;
+};
+
+var enable = function () {
+  meta.enable = function () { /* empty */ };
+  REQUIRED = true;
+  var getOwnPropertyNames = getOwnPropertyNamesModule.f;
+  var splice = uncurryThis([].splice);
+  var test = {};
+  test[METADATA] = 1;
+
+  // prevent exposing of metadata key
+  if (getOwnPropertyNames(test).length) {
+    getOwnPropertyNamesModule.f = function (it) {
+      var result = getOwnPropertyNames(it);
+      for (var i = 0, length = result.length; i < length; i++) {
+        if (result[i] === METADATA) {
+          splice(result, i, 1);
+          break;
+        }
+      } return result;
+    };
+
+    $({ target: 'Object', stat: true, forced: true }, {
+      getOwnPropertyNames: getOwnPropertyNamesExternalModule.f
+    });
+  }
+};
+
+var meta = module.exports = {
+  enable: enable,
+  fastKey: fastKey,
+  getWeakData: getWeakData,
+  onFreeze: onFreeze
+};
+
+hiddenKeys[METADATA] = true;