index.js

'use strict';

const p = require('path');
const transform = require('buble').transform;

const relPath = obj => p.relative(obj.dir, p.format(obj));

module.exports = function (task) {
	task.plugin('buble', {}, function * (file, opts) {
		opts = Object.assign({
			inline: false,
			sourceMap: true,
			file: file.base,
			source: relPath(file)
		}, opts);

		// Transform data
		const output = transform(file.data.toString(), opts);

		// Handle sourcemaps
		if (opts.sourceMap) {
			if (opts.inline) {
				// Append inline sourcemap
				output.code += `\n//# sourceMappingURL=${output.map.toUrl()}`;
			} else {
				output.code += `\n//# sourceMappingURL=${opts.file}.map`;
				// Create new file
				this._.files.push({
					base: `${opts.file}.map`,
					data: output.map.toString(),
					dir: file.dir
				});
			}
		}

		// doc: Return contents as Buffer!
		file.data = new Buffer(output.code);
	});
}