使用 node.js 在 VSCode 中为 Javascript/Typescript 提供更深入的智能感知/帮助文本

Question

I'm very new to programming (in JS/TS specifically and as a whole) but at the moment I try to experiment with node.js and there is one thing in particular that I don't understand with the IntelliSense or the 'helptext' in VSCode.

For example I try to use fs.open() and get the following help text:

open(path: fs.PathLike, flags: fs.OpenMode, mode: fs.Mode | null | undefined, 
callback: (err: NodeJS.ErrnoException | null, fd: number) => void): void

A path to a file. If a URL is provided, it must use the file: protocol.

Asynchronous open(2) - open and possibly create a file.

Now, as a newbie, how do I know what the type fs.PathLike looks like or includes? If I look this method up in the node.js documentation I now know that the type fs.PathLike includes <string> | <Buffer> | <URL> <string> | <Buffer> | <URL> <string> | <Buffer> | <URL> . Aha! So it can be as simple as the path to the file as a string.

But is there any way to see these information directly in VSCode? What fs.PathLike or fs.OpenMode etc. means?

Answer 1

You can't really change the intellisense tooltips, but you can always command+click (mac) or ctrl+click (windows) on anything to drill into it.

In this case if you drilled into fs.open it should take you to these types:

    /**
     * Asynchronous open(2) - open and possibly create a file.
     * @param path A path to a file. If a URL is provided, it must use the `file:` protocol.
     * @param mode A file mode. If a string is passed, it is parsed as an octal integer. If not supplied, defaults to `0o666`.
     */
    export function open(path: PathLike, flags: OpenMode, mode: Mode | undefined | null, callback: (err: NodeJS.ErrnoException | null, fd: number) => void): void;

If you then drill into PathLike you should be taken to this type:

    /**
     * Valid types for path values in "fs".
     */
    export type PathLike = string | Buffer | URL;

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In practice, some type can be very complex. So showing the names of higher complexity types can be a good thing. But it can also makes things opaque. Being able to explore these types can really help, but it will never completely replace looking at official documentation.