You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
53 lines
1.5 KiB
JavaScript
53 lines
1.5 KiB
JavaScript
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
|
|
}; |