Add verbose option

Closes #65

README.md

@@ -181,6 +181,13 @@ Built-in filters:
 
 > A [svg-sprite](https://github.com/jkphl/svg-sprite#configuration-basics) configuration.
 
+###### verbose
+
+> Prints the plugin output to the console.
+
+- Default: `false`
+- Required: `false`
+
 ----
 
 ### The Image

package.json

@@ -33,6 +33,7 @@
   },
   "dependencies": {
     "bluebird": "^3.1.1",
+    "debug": "^2.6.0",
     "fs-extra": "^0.26.4",
     "lodash": "^4.0.0",
     "postcss": "^5.0.14",

src/core.js

@@ -3,6 +3,7 @@ import fs from 'fs-extra';
 import postcss from 'postcss';
 import Promise from 'bluebird';
 import _ from 'lodash';
+import debug from 'debug';
 import RasterFactory from './factories/raster';
 import VectorFactory from './factories/vector';
 
@@ -69,7 +70,8 @@ export const defaults = {
 		svg: {
 			precision: 5
 		}
-	}
+	},
+	verbose: false
 };
 
 /**
@@ -87,8 +89,11 @@ export function prepareFilterBy(opts, result) {
 	opts.filterBy.unshift(image => {
 		return fs.statAsync(image.path)
 			.catch(() => {
-				result.warn(`skip ${image.url} because doesn't exist.`);
-				throw new Error(`Skip ${image.url} because doesn't exist.`);
+				const message = `Skip ${image.url} because doesn't exist.`;
+
+				opts.logger(message);
+
+				throw new Error(message);
 			});
 	});
 }
@@ -135,6 +140,8 @@ export function prepareGroupBy(opts) {
 export function extractImages(root, opts, result) {
 	let images = [];
 
+	opts.logger('Extracting the images...');
+
 	// Search for background & background image declartions
 	root.walkRules((rule) => {
 		const styleFilePath = opts.relativeTo === RELATIVE_TO_RULE ? rule.source.input.file : root.source.input.file;
@@ -175,7 +182,7 @@ export function extractImages(root, opts, result) {
 
 				images.push(image);
 			} else {
-				result.warn(`skip ${image.url} because isn't supported.`);
+				opts.logger(`Skip ${image.url} because isn't supported.`)
 			}
 		}
 	});
@@ -193,6 +200,8 @@ export function extractImages(root, opts, result) {
  * @return {Promise}
  */
 export function applyFilterBy(opts, images) {
+	opts.logger('Applying the filters...');
+
 	return Promise.reduce(opts.filterBy, (images, filterFn) => {
 		return Promise.filter(images, (image) => {
 			return filterFn(image)
@@ -209,6 +218,8 @@ export function applyFilterBy(opts, images) {
  * @return {Promise}
  */
 export function applyGroupBy(opts, images) {
+	opts.logger('Applying the groups...');
+
 	return Promise.reduce(opts.groupBy, (images, groupFn) => {
 		return Promise.map(images, (image) => {
 			return groupFn(image)
@@ -286,6 +297,8 @@ export function setTokens(root, opts, images) {
  * @return {Promise}
  */
 export function runSpritesmith(opts, images) {
+	opts.logger('Generating the spritesheets...');
+
 	return new Promise((resolve, reject) => {
 		const promises = _.chain(images)
 			.groupBy((image) => {
@@ -327,24 +340,25 @@ export function runSpritesmith(opts, images) {
  * @return {Promise}
  */
 export function saveSpritesheets(opts, images, spritesheets) {
+	opts.logger('Saving the spritesheets...');
+
 	return Promise.each(spritesheets, (spritesheet) => {
 		return (
 				_.isFunction(opts.hooks.onSaveSpritesheet) ?
 				Promise.resolve(opts.hooks.onSaveSpritesheet(opts, spritesheet)) :
 				Promise.resolve(makeSpritesheetPath(opts, spritesheet))
 			)
 			.then(( res ) => {
+				if (!res) {
+					throw new Error('postcss-sprites: Spritesheet requires a relative path.');
+				}
 
 				if ( _.isString(res) ) {
 					spritesheet.path = res;
 				} else {
 					_.assign(spritesheet, res);
 				}
 
-				if (!spritesheet.path) {
-					throw new Error('postcss-sprites: Spritesheet requires a relative path.');
-				}
-
 				spritesheet.path = spritesheet.path.replace(/\\/g, '/');
 
 				return fs.outputFileAsync(spritesheet.path, spritesheet.image);
@@ -392,6 +406,8 @@ export function mapSpritesheetProps(opts, images, spritesheets) {
  * @return {Promise}
  */
 export function updateReferences(root, opts, images, spritesheets) {
+	opts.logger('Replacing the references...');
+
 	root.walkComments((comment) => {
 		let rule, image;
 
@@ -577,3 +593,17 @@ export function makeSpritesheetPath(opts, { groups, extension }) {
 export function isToken(commentValue) {
 	return commentValue.indexOf(COMMENT_TOKEN_PREFIX) > -1;
 }
+
+/**
+ * Create a logger that can be disabled in runtime.
+ *
+ * @param  {Boolean} enabled
+ * @return {Function}
+ */
+export function createLogger(enabled) {
+	if (enabled) {
+		debug.enable('postcss-sprites');
+	}
+
+	return debug('postcss-sprites');
+}

src/index.js

@@ -11,7 +11,8 @@ import {
 	runSpritesmith,
 	saveSpritesheets,
 	mapSpritesheetProps,
-	updateReferences
+	updateReferences,
+	createLogger
 } from './core';
 
 /**
@@ -22,6 +23,9 @@ export default postcss.plugin('postcss-sprites', (options = {}) => {
 		// Extend defaults
 		const opts = _.merge({}, defaults, options);
 
+		// Setup the logger
+		opts.logger = createLogger(opts.verbose);
+
 		// Prepare filter & group functions
 		prepareFilterBy(opts, result);
 		prepareGroupBy(opts);
@@ -36,7 +40,7 @@ export default postcss.plugin('postcss-sprites', (options = {}) => {
 			.spread((opts, images, spritesheets) => mapSpritesheetProps(opts, images, spritesheets))
 			.spread((opts, images, spritesheets) => updateReferences(css, opts, images, spritesheets))
 			.spread((root, opts, images, spritesheets) => {
-				result.warn(`${spritesheets.length} ${spritesheets.length > 1 ? 'spritesheets' : 'spritesheet'} generated.`);
+				opts.logger(`${spritesheets.length} ${spritesheets.length > 1 ? 'spritesheets' : 'spritesheet'} generated.`);
 			})
 			.catch((err) => {
 				console.error(`postcss-sprites: An error occurred while processing files - ${err.message}`);

test/03-extract-images.js

@@ -11,7 +11,7 @@ test.beforeEach((t) => {
 	`;
 
 	t.context.ast = postcss.parse(input, { from: '/tmp/test.css' });
-	t.context.opts = Object.assign({}, defaults);
+	t.context.opts = Object.assign({ logger() {} }, defaults);
 });
 
 test('should convert rules to image objects', async (t) => {

test/04-apply-filter-by.js

@@ -5,7 +5,7 @@ import _ from 'lodash';
 import { defaults, prepareFilterBy, extractImages, applyFilterBy } from '../lib/core';
 
 test.beforeEach(async (t) => {
-	t.context.opts = _.merge({}, defaults);
+	t.context.opts = _.merge({ logger() {} }, defaults);
 
 	const input = `
 		.selector-a { background-image: url(circle.png); }

test/05-apply-group-by.js

@@ -10,7 +10,7 @@ test.beforeEach((t) => {
 		.selector-b { background: url(square@2x.png) no-repeat 0 0; }
 	`;
 
-	t.context.opts = _.merge({}, defaults);
+	t.context.opts = _.merge({ logger() {} }, defaults);
 	t.context.ast = postcss.parse(input, { from: '/tmp/test.css' });
 });
 

test/06-set-tokens.js

@@ -5,7 +5,7 @@ import { defaults, extractImages, setTokens } from '../lib/core';
 
 async function run(input) {
 	let root = postcss.parse(input, { from: '/tmp/test.css' });
-	let opts = _.merge({}, defaults);
+	let opts = _.merge({ logger() {} }, defaults);
 	let images;
 
 	[ opts, images ] = await extractImages(root, opts);

test/07-run-spritesmith.js

@@ -8,7 +8,7 @@ import { defaults, extractImages, prepareGroupBy, applyGroupBy, runSpritesmith }
 const readFileAsync = Promise.promisify(fs.readFile);
 
 test.beforeEach((t) => {
-	t.context.opts = _.merge({}, defaults);
+	t.context.opts = _.merge({ logger() {} }, defaults);
 });
 
 test('should generate spritesheets', async (t) => {

test/08-save-spritesheets.js

@@ -16,7 +16,7 @@ import {
 const readFileAsync = Promise.promisify(fs.readFile);
 
 test.beforeEach((t) => {
-	t.context.opts = _.merge({}, defaults);
+	t.context.opts = _.merge({ logger() {} }, defaults);
 });
 
 test('should save spritesheets', async (t) => {
@@ -103,7 +103,7 @@ test('should throw error if path is empty', async (t) => {
 	[ opts, images ] = await extractImages(ast, t.context.opts);
 	[ opts, images, spritesheets ] = await runSpritesmith(t.context.opts, images);
 
-	t.throws(saveSpritesheets(images, t.context.opts, spritesheets));
+	t.throws(saveSpritesheets(t.context.opts, images, spritesheets));
 });
 
 test('should use Promise result provided by book', async (t) => {

test/09-map-spritesheet-props.js

@@ -16,7 +16,7 @@ import {
 const readFileAsync = Promise.promisify(fs.readFile);
 
 test.beforeEach((t) => {
-	t.context.opts = _.merge({}, defaults);
+	t.context.opts = _.merge({ logger() {} }, defaults);
 });
 
 test('should add coords & spritePath to every image', async (t) => {

test/10-update-references.js

@@ -17,7 +17,7 @@ import {
 const readFileAsync = Promise.promisify(fs.readFile);
 
 test.beforeEach((t) => {
-	t.context.opts = _.merge({}, defaults);
+	t.context.opts = _.merge({ logger() {} }, defaults);
 });
 
 test('should update CSS declarations', async (t) => {