You can also use [`TypeArray.from()`][3] method on all [Typed Arrays][1] to convert between normal arrays:






    const values = [-1, 94, 43, 34]

    const byteArr = Int8Array.from(values)
    const original = Array.from(byteArr)

    console.log({ byteArr, original })





**Bonus**: This works in node *and also* the browser

[1]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Typed_arrays
[2]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/from
[3]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/from

I am trying to determine what encoding scheme will give me the numbers -1 or -40 (the starting numbers for the file) for a jpeg file type.

A rest api I'm working on is expecting a byte array that looks like [-1, 94, 43, 34, etc]. In node.js I can have the byte array as hex, or any other encoding type, but I seem not able to get -1 or -40 for the starting value whichever encoding scheme I try.

In the documentation I saw an example in Java which uses the "toByteArray()" function, which seems to get the starting values (-1 or -40). Can anyone help me?