Refactor. Update dependencies. Update tests. Make img plugin async.

lib/img.js

@@ -0,0 +1,48 @@
+const co = require('co');
+const datauri = require('datauri').promises;
+const isLocalPath = require('is-local-path');
+const isTemplateExpression = require('./is-template-expression');
+const path = require('path');
+const R = require('ramda');
+
+const forEachIndexed = R.addIndex(R.forEach);
+const resolve = R.curry((a,b) => path.resolve(a,b));
+
+/**
+ * Inline sourced image files
+ *
+ * @param {Object} $
+ * 	Parsed HTML source to inline
+ * @param {String} filename
+ * 	Filename used to resolve relative sources being inlined
+ */
+const inlineImg = co.wrap(function * ($, filename) {
+	var files;
+	const basedir = path.dirname(filename);
+	const getAttr = R.curry((attr, element) => $(element).attr(attr));
+	const setAttr = R.curry((attr, element, value) => $(element).attr(attr, value));
+	const getFilename = R.pipe(getAttr('src'), resolve(basedir));
+	try {
+		const images = $('img')
+			.filter((index, element) => {
+				const source = $(element).attr('src');
+				return isLocalPath(source) && !isTemplateExpression(source);
+			})
+			.toArray();
+
+		const filenames = R.map(getFilename, images);
+		files = R.uniq(filenames);
+		const uris = yield R.map(datauri, filenames);
+
+		forEachIndexed((image, index) => setAttr('src', image, uris[index]), images);
+		
+		return { $, files };
+	}
+	catch (error) {
+		error.filename = filename;
+		error.files = files;
+		throw error;
+	}
+});
+
+module.exports = inlineImg;