main

Author: sharpchen

docs/document/JavaScript/docs/Type System/Array.md

@@ -0,0 +1,3 @@
+# Measure
+
+

docs/document/JavaScript/docs/Type System/Function.md

@@ -0,0 +1,38 @@
+# Conditional Keys
+
+Instead of iterating over all properties/entries in a type, we can do the following before we transform the target types.
+
+- Filter keys: filter out keys that we don't want to include base on a conditional type expression.
+- Transform keys: transform keys before we transform traget type.
+
+## Synopsis
+
+`as` keyword was introduced here to connect with conditional type expression.
+
+```ts
+type <name> = {
+    [<type> in <type> as <condition>]: <type>
+}
+```
+
+## Filter Keys
+
+The following example shows how to extract property names that're not singular typed(not an object or a collection).
+All keys that didn't satisfies the condition `T[K] extends object` will be replaced as `never`, which is the empty type. In other words, they will be filtered.
+And lastly the target type can be arbitrary since we don't need it, all we need is the keys.
+
+```ts twoslash
+const foo = {
+    bar = 123,
+    baz = '123',
+    goo = [1, 2, 3],
+    foo = { foo = {} }
+}
+
+type KeyOfSingularTypedProperty<T> = keyof {
+    [K in keyof T as T[K] extends object ? never : K]: any // [!code highlight] 
+}
+
+type SingularKeyOfFoo = KeyOfSingularTypedProperty<typeof foo>
+```
+

docs/document/JavaScript/docs/Type System/Object.md

@@ -14,7 +14,7 @@ export const documentMap = {
   Docker: { icon: '🐳', description: 'Ultimate Docker' },
   Git: { icon: '😸', description: 'Git mastery' },
   JavaScript: { icon: '😅', description: '' },
-  SQL: { icon: '🦭', description: '' },
+  // SQL: { icon: '🦭', description: '' },
   TypeScript: { icon: '🤯', description: '' },
   // VBA: { icon: '💩', description: 'VBA for excel' },
   // Vue3: { icon: '⚡', description: '' },

docs/document/JavaScript/docs/Type System/Primitive Types.md

@@ -53,7 +53,7 @@ class SidebarService implements ISidebarService {
       if (Object.prototype.hasOwnProperty.call(subs, index)) {
         const sub = subs[index];
         const currentSidebarItem: DefaultTheme.SidebarItem = {
-          collapsed: false,
+          collapsed: true,
           text: solveSharpSign(sub.name.replace(/^\d+\.\s*/, '')), // remove leading index
           items: this.transformFolderToSidebarItem(sub, `${base}/${folder.name}`),
         };