const isRequired = require('./isRequired.js');

/**
 * Finds all chunks of a webpack compilation object and maps the chunk name
 * to the first containing file.
 *
 * @param {Object} compilation - a webpack compilation object
 * @param {Object[]} compilation.chunks - an array of webpack chunks
 * @return {Object}
 */
function getChunkFiles (compilation = isRequired('compilation')) {
    return compilation.chunks.reduce(function mapChunksToFiles(files, chunk) {
        files[chunk.name] = chunk.files;
        return files;
    }, {});
}

module.exports = getChunkFiles;