Rollup optional input

Question

Is there a way in Rollup to skip an input if it was not found? At the moment the build fails with Error: Could not resolve entry module (src/index.js) as soon as the file was not found.

I went through the documentation and searched around, but I can't seem to find an option or hook to achieve this. In the simplified example below, I would like to continue to the next page.js build when the src/index.js was not found.

export default [
    {
        input: 'src/index.js',
        output: [
            {
                file: 'dist/esm/index.esm.js',
                format: 'esm',
            },
            {
                file: 'dist/cjs/index.js',
                format: 'cjs',
            },
        ],
        plugins: [
            // ...
        ],
    },
    {
        input: 'page.js',
        output: [
            {
                file: 'dist/esm/page.esm.js',
                format: 'esm',
            },
            {
                file: 'dist/cjs/page.js',
                format: 'cjs',
            },
        ],
        plugins: [
            // ...
        ],
    },
];

Answer 1

no idea if this will work or not, code to illstrate further what I'm talking about as a potential solution.

const fs = require('fs');
const path = 'src/index.js';

const config = [
{
        input: 'page.js',
        output: [
            {
                file: 'dist/esm/page.esm.js',
                format: 'esm',
            },
            {
                file: 'dist/cjs/page.js',
                format: 'cjs',
            },
        ],
        plugins: [
            // ...
        ],
}];

const determineFileExistsForConfig = () => {
  try {
     // if index exists, add to the config
     if (fs.existsSync(path)) {
       config.push({
        input: 'src/index.js',
        output: [
            {
                file: 'dist/esm/index.esm.js',
                format: 'esm',
            },
            {
                file: 'dist/cjs/index.js',
                format: 'cjs',
            },
        ],
        plugins: [
            // ...
        ],
    });
     }
  } catch(err) {
    return config;
  }
}


const finalConfig = determineFileExistsForConfig();
export default finalConfig;