get-typeandmime/src/index.js

npm package for generating its file-type on basis of magic numbers!!

const fs = require("fs");
const types = require("./fileTypes");
const magicNumbers = types;

// Get file Mime and signs based on Type of File
function getFileType(filePath) {
  const buffer = Buffer.alloc(8);

  const fd = fs.openSync(filePath, "r");
  fs.readSync(fd, buffer, 0, 8, 0);
  fs.closeSync(fd);

  const fileHeader = buffer.toString("hex").toUpperCase();
  for (const [fileType] of Object.entries(magicNumbers)) {
    const fileCheck = types[fileType].signs[0].split(",")[1];

    if (fileHeader.startsWith(fileCheck)) {
      return { Type: fileType, mime: `${magicNumbers[fileType].mime}` };
    }
  }

  return "Unsupported file type";
}

// verify whether the file extension is present in list or not
function getFileSign(fileExtension) {
  if (types[fileExtension]) {
    return types[fileExtension];
  } else {
    return "Unsupported file type by this NPM Package, Please contact author to add it up!!";
  }
}

// get file type from remote location
async function getStreamFileType(file) {
  const result = await fetch(file);

  return (await result.blob()).type;
}



// Expecting string argument for function
module.exports = { getFileType, getFileSign, getStreamFileType};