Zazama / node-id3

import * as fs from "fs"

import { isBuffer } from "../util"

function getPictureMimeTypeFromBuffer(pictureBuffer: Buffer) {

    if (

        pictureBuffer.length > 3 &&

        pictureBuffer.compare(Buffer.from([0xff, 0xd8, 0xff]), 0, 3, 0, 3) === 0

    ) {

        return "image/jpeg"

    }

    if (

        pictureBuffer.length > 8 &&

        pictureBuffer.compare(Buffer.from([0x89, 0x50, 0x4E, 0x47, 0x0D, 0x0A, 0x1A, 0x0A]), 0, 8, 0, 8) === 0

    ) {

        return "image/png"

    }

    return ""

}

export function retrievePictureAndMimeType({

    filenameOrBuffer,

    mimeType

}: {

    filenameOrBuffer?: Buffer | string

    mimeType?: string

}) {

    if (!filenameOrBuffer) {

        throw new TypeError("Missing image buffer or filename")

    }

    const pictureBuffer = isBuffer(filenameOrBuffer) ?

        filenameOrBuffer : fs.readFileSync(filenameOrBuffer)

    return {

        pictureBuffer,

        mimeType: mimeType ?? getPictureMimeTypeFromBuffer(pictureBuffer)

    }

}