--- /dev/null
+var META = require('./_uid')('meta')
+ , isObject = require('./_is-object')
+ , has = require('./_has')
+ , setDesc = require('./_object-dp').f
+ , id = 0;
+var isExtensible = Object.isExtensible || function(){
+ return true;
+};
+var FREEZE = !require('./_fails')(function(){
+ return isExtensible(Object.preventExtensions({}));
+});
+var setMeta = function(it){
+ setDesc(it, META, {value: {
+ i: 'O' + ++id, // object ID
+ w: {} // weak collections IDs
+ }});
+};
+var fastKey = function(it, create){
+ // return primitive with prefix
+ if(!isObject(it))return typeof it == 'symbol' ? it : (typeof it == 'string' ? 'S' : 'P') + it;
+ if(!has(it, META)){
+ // 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
+ setMeta(it);
+ // return object ID
+ } return it[META].i;
+};
+var getWeak = function(it, create){
+ if(!has(it, META)){
+ // 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
+ setMeta(it);
+ // return hash weak collections IDs
+ } return it[META].w;
+};
+// add metadata on freeze-family methods calling
+var onFreeze = function(it){
+ if(FREEZE && meta.NEED && isExtensible(it) && !has(it, META))setMeta(it);
+ return it;
+};
+var meta = module.exports = {
+ KEY: META,
+ NEED: false,
+ fastKey: fastKey,
+ getWeak: getWeak,
+ onFreeze: onFreeze
+};
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