Add JavaScript scope and closure documentation

memoriaXII · Mar 17, 2024 · b7320ae · b7320ae
1 parent e10a5a4
commit b7320ae
Show file tree

Hide file tree

Showing 3 changed files with 26 additions and 0 deletions.
diff --git a/docs/02_javascript/basic/image-3.png b/docs/02_javascript/basic/image-3.png
diff --git a/docs/02_javascript/basic/image-4.png b/docs/02_javascript/basic/image-4.png
diff --git a/docs/02_javascript/basic/scope-closure.md b/docs/02_javascript/basic/scope-closure.md
@@ -0,0 +1,26 @@
+---
+
+sidebar_position: 1
+tags:
+
+- scope
+
+---
+
+# Scope
+
+Where and how to look for things. JS have two lexical scopes global and function
+
+變數在程式中可以被存取的範圍，可分為區域變數，全域變數。
+
+![alt text](image-3.png)
+
+# Closure
+
+Closure is when a function “remembers” its lexical scope even when the function is executed outside that lexical scope. The combination of the function and it’s environment is known as a closure.
+
+閉包是個捕捉了外部函式變數（或使之繼續存活）的函式，它包含了一個函式，以及函式被建立時所在的環境
+
+![alt text](image-4.png)
+
+基本上函式離開執行環境時，也會同時將佔用的記憶體空間給釋放出來。例如以上 x變數應該在執行完畢就會在 memory (記憶體) 中被清掉。但因為 closure 特性此 x變數還會繼續被保留