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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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