Adding more sources types into ImportFactor.from

[Siemienik]

As @Metastasis mentioned in #4 (comment). Current factory has possibility only for reading workbook from local file system, what can't works under browser because security purposes.

Actual

The ImportFactory.from accept only filePath which is a string:

https://github.com/Siemienik/xlsx-import/blob/90c2b76564bd87433de19a9e8f55b9e064d14e09/src/ImporterFactory.ts#L6-L11

Expected

ImportFactory should recognise type of argument and knowing this choose how to handle it.

Type	What is	Should do
string	File path	If node: read file from localsystem
string	Data url	Get ArrayBuffer
string	Buffer representation *	Transform to ArrayBuffer
Buffer|ArrayBuffer	Buffer	Read indirectly from buffer
none of above	unknown	I haven't idea yet, probably should throw an error

• As @Metastasis mention:

I realized that string can also be a buffer so probably my implementation is broken (string can represent buffer as well as file path).

Please keep in mind, that samples Readme link into this issue - should be updated when issue become done.

Further (if requested)

Please do not it now

Type	What is	Should do
string	File url	Download from url and read file as ArrayBuffer

[Metastasis]

@Siemienik
This issue looks fine but
I'm not sure about File Url part since It looks for me like too much responsibility. From another point of view It could be a lot of copy-paste code in the client therefore this feature should be implemented
I think we could implement this and see what happens next:) (I assume somebody will create an issue if something broken)

[Siemienik]

I'm not sure about File Url part since It looks for me like too much responsibility

Right, I considered a lot about that. May we should implement first version without this and add it if requested. WDYT?

[Metastasis]

@Siemienik
Yeah, I think we could omit File Url

[Siemienik]

connected with #196