> For the complete documentation index, see [llms.txt](https://xiaohesong.gitbook.io/today-i-learn/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://xiaohesong.gitbook.io/today-i-learn/front-end/javascript/you-dont-known-js.md).

# you-dont-known-js

- [async\&performance](https://xiaohesong.gitbook.io/today-i-learn/front-end/javascript/you-dont-known-js/async-and-performance.md)
- [Chapter 1: Asynchrony: Now & Later](https://xiaohesong.gitbook.io/today-i-learn/front-end/javascript/you-dont-known-js/async-and-performance/ch1-asynchrony-now-and-later.md)
- [Chapter 2: Callbacks](https://xiaohesong.gitbook.io/today-i-learn/front-end/javascript/you-dont-known-js/async-and-performance/ch2-callbacks.md)
- [Chapter 3: Promises](https://xiaohesong.gitbook.io/today-i-learn/front-end/javascript/you-dont-known-js/async-and-performance/ch3-async-and-performance.md)
- [Chapter 4: Generators](https://xiaohesong.gitbook.io/today-i-learn/front-end/javascript/you-dont-known-js/async-and-performance/ch4-generators.md)
- [scope & closures](https://xiaohesong.gitbook.io/today-i-learn/front-end/javascript/you-dont-known-js/scope-and-closures.md)
- [apA](https://xiaohesong.gitbook.io/today-i-learn/front-end/javascript/you-dont-known-js/scope-and-closures/apa.md)
- [apB](https://xiaohesong.gitbook.io/today-i-learn/front-end/javascript/you-dont-known-js/scope-and-closures/apb.md)
- [apC](https://xiaohesong.gitbook.io/today-i-learn/front-end/javascript/you-dont-known-js/scope-and-closures/apc.md)
- [apD](https://xiaohesong.gitbook.io/today-i-learn/front-end/javascript/you-dont-known-js/scope-and-closures/apd.md)
- [chapter1-what-is-scope](https://xiaohesong.gitbook.io/today-i-learn/front-end/javascript/you-dont-known-js/scope-and-closures/chapter1-what-is-scope.md)
- [chapter2-lexical-scope](https://xiaohesong.gitbook.io/today-i-learn/front-end/javascript/you-dont-known-js/scope-and-closures/chapter2-lexical-scope.md)
- [chapter3-function-vs-block-scope](https://xiaohesong.gitbook.io/today-i-learn/front-end/javascript/you-dont-known-js/scope-and-closures/chapter3-function-vs-block-scope.md)
- [chapter4-hoisting](https://xiaohesong.gitbook.io/today-i-learn/front-end/javascript/you-dont-known-js/scope-and-closures/chapter4-hoisting.md)
- [chapter5-scope-closure](https://xiaohesong.gitbook.io/today-i-learn/front-end/javascript/you-dont-known-js/scope-and-closures/chapter5-scope-closure.md)
- [this & object prototypes](https://xiaohesong.gitbook.io/today-i-learn/front-end/javascript/you-dont-known-js/this-and-object-prototypes.md)
- [chapter1-this-or-that](https://xiaohesong.gitbook.io/today-i-learn/front-end/javascript/you-dont-known-js/this-and-object-prototypes/chapter1-this-or-that.md)
- [chapter2-this-make-sense](https://xiaohesong.gitbook.io/today-i-learn/front-end/javascript/you-dont-known-js/this-and-object-prototypes/chapter2-this-make-sense.md)
- [chapter3-objects](https://xiaohesong.gitbook.io/today-i-learn/front-end/javascript/you-dont-known-js/this-and-object-prototypes/chapter3-objects.md)
- [chapter4-mixing(up)-class-object](https://xiaohesong.gitbook.io/today-i-learn/front-end/javascript/you-dont-known-js/this-and-object-prototypes/chapter4-mixing-up-class-object.md)
- [chapter5-prototype](https://xiaohesong.gitbook.io/today-i-learn/front-end/javascript/you-dont-known-js/this-and-object-prototypes/chapter5-prototype.md)
- [chapter6-behavior-delegation](https://xiaohesong.gitbook.io/today-i-learn/front-end/javascript/you-dont-known-js/this-and-object-prototypes/chapter6-behavior-delegation.md)
- [types\&grammer](https://xiaohesong.gitbook.io/today-i-learn/front-end/javascript/you-dont-known-js/types-and-grammer.md)
- [Chapter1-Types](https://xiaohesong.gitbook.io/today-i-learn/front-end/javascript/you-dont-known-js/types-and-grammer/chapter1-types.md)
- [Chapter2-Values](https://xiaohesong.gitbook.io/today-i-learn/front-end/javascript/you-dont-known-js/types-and-grammer/chapter2-values.md)
- [Chapter3-Natives](https://xiaohesong.gitbook.io/today-i-learn/front-end/javascript/you-dont-known-js/types-and-grammer/chapter3-natives.md)
- [Chapter4-coercion](https://xiaohesong.gitbook.io/today-i-learn/front-end/javascript/you-dont-known-js/types-and-grammer/chapter4-coercion.md)
- [Chapter5-grammer](https://xiaohesong.gitbook.io/today-i-learn/front-end/javascript/you-dont-known-js/types-and-grammer/chapter5-grammer.md)
- [up & going](https://xiaohesong.gitbook.io/today-i-learn/front-end/javascript/you-dont-known-js/up-and-going.md)
- [chapter1-into-programming](https://xiaohesong.gitbook.io/today-i-learn/front-end/javascript/you-dont-known-js/up-and-going/chapter1-into-programming.md)
- [chapter2-into-javascript](https://xiaohesong.gitbook.io/today-i-learn/front-end/javascript/you-dont-known-js/up-and-going/chapter2-into-javascript.md)
- [chapter3-into-YDKJS](https://xiaohesong.gitbook.io/today-i-learn/front-end/javascript/you-dont-known-js/up-and-going/chapter3-into-ydkjs.md)