🍄function

🚧 under construction -> named function

JS ⟩ value ⟩ object ⟩ function

an object that can be called (supports the [[Call]] internal method).

• its name (or a variable that refers to it) is an identifier.

// function declarations
function  f() { ... }          // normal function
function* f() { ... }          // generator function
async function  f() { ... }    // async function
async function* f() { ... }    // async generator function

⭐️ 重點

⚖️parameter vs. argument

every function

• is actually a Function object.

• is a closure.

In JavaScript, function arguments are always passed by value. (values of the variables are copied into the function arguments)

👉 JavaScript Tutorial » Understanding JavaScript Pass-By-Value

• function vs. class ( 👉 class ⟩ #zhong-dian, function 的「💾 程式」 )

• function vs. constructor

method is a function.

a closure (or IIFE) can be used to create a scope to hide variables/functions.

A "variable" is just a property of the environment record (associated with the currently executing block /function /module /script).

🔴 主題

• creating functions

  • function declaration

  • using Function constructor

  • function expression - an expression that evaluates to a function.

    • arrow function

    • IIFE - immediately invoked function expression

• types of functions

  • anonymous function vs. named function 🚧

  • async function

  • callback - a function as an argument.

  • recursive function - a function that calls itself.

  • nested function

  • closure

  • constructor

• accessing functions

  • function name 🚧

• calling functions

  • parameter / argument

  • default parameter

• features of functions

  • function scope - scope created by function.

  • new.target - detect whether a function/constructor was called using new.

  • function boundary

• function transformers

  • decorator

  • memoization - make a function "remember" its return values.

• other topics

  • helper functions

👥 相關

• a function

  • is an object.

  • is a closure.

• the following are functions：

  • every method

  • every class

  • every constructor (supports the [[Construct]] internal method).

• closure can be used as a function with private property (functions/variables)❗(👉 closure: manage grades)

📗 參考

• JS.info ⟩ Proxy ⟩ internal method [[Call]].

📘 手冊

• function declaration

• Function

• Functions - object method/getter/setter are all functions.

🚧

• named function