62 lines
1.7 KiB
JavaScript
62 lines
1.7 KiB
JavaScript
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var hiddenKeys = require('../internals/hidden-keys');
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var isObject = require('../internals/is-object');
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var has = require('../internals/has');
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var defineProperty = require('../internals/object-define-property').f;
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var uid = require('../internals/uid');
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var FREEZING = require('../internals/freezing');
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var METADATA = uid('meta');
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var id = 0;
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var isExtensible = Object.isExtensible || function () {
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return true;
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};
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var setMetadata = function (it) {
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defineProperty(it, METADATA, { value: {
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objectID: 'O' + ++id, // object ID
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weakData: {} // weak collections IDs
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} });
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};
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var fastKey = function (it, create) {
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// return a primitive with prefix
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if (!isObject(it)) return typeof it == 'symbol' ? it : (typeof it == 'string' ? 'S' : 'P') + it;
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if (!has(it, METADATA)) {
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// can't set metadata to uncaught frozen object
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if (!isExtensible(it)) return 'F';
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// not necessary to add metadata
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if (!create) return 'E';
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// add missing metadata
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setMetadata(it);
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// return object ID
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} return it[METADATA].objectID;
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};
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var getWeakData = function (it, create) {
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if (!has(it, METADATA)) {
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// can't set metadata to uncaught frozen object
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if (!isExtensible(it)) return true;
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// not necessary to add metadata
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if (!create) return false;
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// add missing metadata
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setMetadata(it);
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// return the store of weak collections IDs
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} return it[METADATA].weakData;
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};
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// add metadata on freeze-family methods calling
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var onFreeze = function (it) {
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if (FREEZING && meta.REQUIRED && isExtensible(it) && !has(it, METADATA)) setMetadata(it);
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return it;
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};
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var meta = module.exports = {
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REQUIRED: false,
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fastKey: fastKey,
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getWeakData: getWeakData,
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onFreeze: onFreeze
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};
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hiddenKeys[METADATA] = true;
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