This commit is contained in:
Violet.Lee 2019-08-30 05:35:48 +09:00 committed by GitHub
parent 95597b8fda
commit 6fc41bac7a
No known key found for this signature in database
GPG key ID: 4AEE18F83AFDEB23

View file

@ -155,7 +155,7 @@ We can avoid it by switching to `WeakMap` instead:
```js
// 📁 visitsCount.js
let visitsCountMap = new WeakMap(); // map: user => visits count
let visitsCountMap = new WeakMap(); // weakmap: user => visits count
// increase the visits count
function countUser(user) {
@ -164,7 +164,7 @@ function countUser(user) {
}
```
Now we don't have to clean `visitsCountMap`. After `john` object becomes unreachable by all means except as a key of `WeakMap`, it gets removed from memory, along with the information by that key from `WeakMap`.
Now we don't have to clean `visitsCountMap`. After `john` object becomes unreachable by all means except as a key of `WeakMap`, it gets removed from memory, along with the information by that key from `WeakMap`.
## Use case: caching