What is file scope in javascript

问题

What is variable declared within file scope in javascript?
Is there anything file scope, considering multiple files are used in an app.

回答1:

ES6 modules form their own file scope (as if the entire contents of the file were wrapped in a function).

Variables declared in a module are completely inaccessible from outside that module (unless they're exported).

回答2:

In JavaScript, there are only 3 types of scope:

1. Global Scope (i.e. every variable/function defined outside functions in a file or multiple files)
2. Functional Scope (i.e. every variable/function defined within the function)
3. Closure Scope (i.e. code block/function having access to its surrounding lexical scope)

来源：https://stackoverflow.com/questions/44916179/what-is-file-scope-in-javascript