Incomplete filesystem declarations

[jozefchutka]

Please consider updating declarations following my updates. You might want to update existing declaration or add new ones:

FileSystem related:

type PermissionOptions_ = {
	readonly mode:"readwrite";
}

type FileSystemHandle_ = FileSystemDirectoryHandle | FileSystemFileHandle;

// https://developer.mozilla.org/en-US/docs/Web/API/FileSystemHandle
interface FileSystemDirectoryHandle {
	readonly values:() => FileSystemHandle_[];
	readonly queryPermission:(options:PermissionOptions_) => Promise<"granted" | "prompt" | unknown>;
	readonly requestPermission:(options:PermissionOptions_) => Promise<"granted" | unknown>;
}

// https://developer.mozilla.org/en-US/docs/Web/API/FileSystemFileHandle
interface FileSystemFileHandle {
	// already available in chrome
	// https://github.com/whatwg/fs/pull/10#issuecomment-1385992738
	readonly move:(newName:string) => Promise<void>;
}

// https://wicg.github.io/file-system-access/#enumdef-wellknowndirectory
type WellKnownDirectory = "desktop" | "documents" | "downloads" | "music" | "pictures" | "videos";

// https://wicg.github.io/file-system-access/#api-filepickeroptions-starting-directory
// https://wicg.github.io/file-system-access/#api-showdirectorypicker
type StartingDirectory = {
	readonly id?:string; // If id’s length is more than 32, throw a TypeError.
	readonly startIn?:FileSystemHandle | WellKnownDirectory;
}

type FilePickerOptionsType = {
	readonly description?:string;
	readonly accept:Record<string, ReadonlyArray<string>>;
}

// https://developer.mozilla.org/en-US/docs/Web/API/window/showSaveFilePicker
type SaveFilePickerOptions = {
	readonly excludeAcceptAllOption?:boolean;

	// https://github.com/WICG/file-system-access/blob/main/SuggestedNameAndDir.md
	readonly startIn?:"desktop" | "documents" | "downloads" | "music" | "pictures" | "videos";

	// https://github.com/WICG/file-system-access/blob/main/SuggestedNameAndDir.md#interaction-of-suggestedname-and-accepted-file-types
	readonly suggestedName?:string;

	readonly types?:FilePickerOptionsType[];
}

// https://developer.mozilla.org/en-US/docs/Web/API/window/showOpenFilePicker
// https://wicg.github.io/file-system-access/#api-filepickeroptions
type OpenFilePickerOptions = StartingDirectory & {
	readonly multiple?:boolean;
	readonly excludeAcceptAllOption?:boolean;
	readonly types?:FilePickerOptionsType[];
}

const showOpenFilePicker:(options?:OpenFilePickerOptions) => Promise<(FileSystemFileHandle | FileSystemDirectoryHandle)[]>;
const showDirectoryPicker:(options?:StartingDirectory) => Promise<FileSystemDirectoryHandle>;
const showSaveFilePicker:(options?:SaveFilePickerOptions) => Promise<FileSystemFileHandle>;

interface DataTransferItem {
	getAsFileSystemHandle():Promise<FileSystemHandle_>;
}

Notice I am using FileSystemHandle_ b/c its provides better guarding in code compared to FileSystemHandle i.e.

if (handle.kind==="directory")
    handle.values() // only available on FileSystemDirectoryHandle
else
    handle.move() // only available on FileSystemFileHandle

[saschanaz]

I think all of these also fall into https://github.com/microsoft/TypeScript-DOM-lib-generator/issues/1556#issuecomment-1536452712.

[jozefchutka]

Can we at least consider improvements of current FileSystemHandle, I mean there is no obvious narrowing from FileSystemHandle to FileSystemDirectoryHandle (or FileSystemFileHandle)

Following would be nice to achieve:

const handle:FileSystemHandle;
if (handle.kind === "directory")
    // handle to be narrowed to FileSystemDirectoryHandle so ie. handle.resolve() is available
else
    // handle to be narrowed to FileSystemFileHandle so ie. handle.getFile() is available

Right now, an explicit casting is needed

if (handle.kind === "directory")
    <FileSystemDirectoryHandle>handle...

[saschanaz]

That's #1494. Perhaps there can be type FileSystemAnyHandle = FileSystemDirectoryHandle | FileSystemFileHandle; and others APIs should use it instead of FileSystemHandle.