Get file type using fs/node.js-CodePudding

I have a folder with few files and I need to get type/extension of the file matching with the number I generate in my num variable, so is there any way I can do it?

My current code is:

fs.readdir(dir, (err, files) => {
  const num = (Math.floor(Math.random() * files.length)   1).toString();
  // here I need to get file type/extension
}

files variable return this: ['1.jpg', '2.png', '3.gif']

CodePudding user response：

To find a file in a list of files regardless of the extension, use path.basename and path.extname on the files in the list to chop the extensions. For a single search, use files.find().

const filename = files.find(x => path.basename(x, path.extname(x)) === num.toString()))

However, for random selection purposes, it may be better to simply take a random entry from files. The reason is, if the files are all sequentially numbered it's the same thing, but if they aren't all sequentially numbered the above can break.

const filename = files[num] // and take away   1 from num

CodePudding user response：

Instead of matching the whole file name, You can just generate a random number in ArrayList and get that file.

const fs = require("fs");
const path = require("path");

fs.readdir(__dirname, (err, files) => {
  const randomNum = Math.floor(Math.random() * files.length);
  // get the random file
  let randomFileName = files[randomNum];
  console.log(randomFileName);

  /// Get unique exts
  const exts = [...new Set(files.map((name) => path.extname(name)))];
  console.log(exts);
  const randomExt = Math.floor(Math.random() * exts.length);
  
  // Get file with random ext
  randomFileName = files.find((x) => path.extname(x) === exts[randomExt]);
  console.log(randomFileName);
});