Rollup configuration for filename hashes with a single input and output file

Question

Say that I have this basic rollup.config.js file.

export default {
    input: 'src/main.js',
    output: {
        format: 'iife',
        file: 'dist/bundle.js',
    }
};

I want the output file to have its hash in the file name (e.g. bundle-9f02a82b.js). From what I can tell from the docs, the correct way to do this is with options.entryFileNames. However, that setting doesn’t seem to have any effect when outputting to options.file.

I have seen some people online mention that you can use [hash] in output.file, but that doesn’t seem to actually work.

export default {
    input: 'src/main.js',
    output: {
        format: 'iife',
        file: 'dist/bundle-[hash].js', // this doesn’t work
    },
};

Answer 1

In order to get a hashed file name, you will have to replace output.file with output.dir and output.entryFileNames.

In your example that would be:

export default {
    input: 'src/main.js',
    output: {
        format: 'iife',
        dir: 'build',
        entryFileNames: 'bundle-[hash].js',
    },
};