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- 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;
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