If you are working with TypeScript and need to filter only JavaScript files (.js) after the TypeScript build process, you may encounter some challenges. The fs.readdirSync method in Node.js returns an array of all files in a directory, but it doesn’t provide a built-in way to filter files by their extension. However, there are a few solutions you can use to achieve this.

1. Using the path.extname method

The path.extname method in Node.js extracts the file extension from a given file path. You can utilize this method to filter only JavaScript files (.js) after the TypeScript build. Here’s an example:

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

const directoryPath = '/path/to/directory';

const files = fs.readdirSync(directoryPath);

const jsFiles = files.filter(file => path.extname(file) === '.js');

console.log(jsFiles);
    

In the above code snippet, we first import the fs and path modules. Then, we define the directory path from which we want to retrieve the files. Next, we use fs.readdirSync to get all the files in the directory. Finally, we filter the files array using the path.extname method to only keep the files with the .js extension.

2. Using a regular expression

Another approach is to use a regular expression to filter only JavaScript files (.js). Here’s an example:

const fs = require('fs');

const directoryPath = '/path/to/directory';

const files = fs.readdirSync(directoryPath);

const jsFiles = files.filter(file => /.js$/.test(file));

console.log(jsFiles);
    

In this code snippet, we again use fs.readdirSync to retrieve all the files in the directory. Then, we filter the files array using a regular expression /.js$/ to match only the files with the .js extension.

Both of these solutions will give you an array of JavaScript files (.js) after the TypeScript build process. You can then perform further operations on these files as needed.

Remember to replace ‘/path/to/directory’ with the actual directory path in your code.

Conclusion

Filtering only JavaScript files (.js) after the TypeScript build process can be accomplished using the path.extname method or a regular expression. Both solutions provide a way to extract the file extension and filter the files accordingly. Choose the approach that suits your needs and integrate it into your TypeScript project.