Draft: Added dump function to allow to write back arrays on files

[vallsv]

Hi,

Here is an implementation to create npy binary data from a TypedArray.

It was rebased on top of #52. This closes #53.

It can be used the following way:

import * as fs from 'fs';
import * as npyjs from 'npyjs';

const myarray = new Uint8Array([1, 2, 3, 4});
const shape = [2, 2];
const bytes = npyjs.dump(myarray, shape);
fs.writeFileSync('myarray.npy', new Uint8Array(bytes));

Notice that i have added the function isLittleEndian() to check the endianness of the system. This can also be used while loading an array for safety.

[j6k4m8]

Wow, this is super! Thank you @vallsv! I've changed the merge target to the modernize-repo branch so I can merge this in ASAP; is this ready to go or do you want me to wait before merging?

[vallsv]

Hi, thanks. It's up to you. I put draft because you are working in the other PR, but it's done. You can do what ever you want with it. Or also asking me changes.

[j6k4m8]

Amazing — I'm going to merge it in!! Thank you again for this great work!