The term originated as a whimsical irregular form of the verb think. It refers to the original use of thunks in ALGOL 60 compilers, which required special analysis (thought) to determine what type of routine to generate.

怎样支持递归定义/初始化变量（相较于几乎所有现代语言都支持函数定义递归）？

redux-thunk does: it is a middleware that looks at every action that passes through the system, and if it’s a function, it calls that function.

In addition to these development tool middleware, it also adds redux-thunk by default, since thunks are the basic recommended side effects middleware for Redux.

I'm a Redux maintainer and creator of Redux Toolkit. FWIW, nothing about making async calls with Redux changes with Redux Toolkit. You'd still use an async middleware (typically redux-thunk), fetch data, and dispatch actions with the results.

It’s also common to see getters being used with Promises, since Promises are known to not be reusable computations, so that wrapping a Promise constructor in a getter (also known as “factory” or “thunk”) makes it reusable.