Add option to specify default plugin options (closes #11) (#21)

* Add option to specify default plugin options (closes #11)

* Fix Object.assign in Node <= 0.12

* Rename `defaultPluginOptions` to the less verbose `options`

* Use object spread over assign polyfill

README.md

@@ -85,6 +85,25 @@ plugin, for instance.
 postcss([ use({ resolveFromFile: true, modules: '*' }) ]);
 ```
 
+##### options
+
+Type: `object` (default: `{}`)
+
+Default options for plugins, keyed by plugin name. If both the default and the specified options are objects, they are merged. Otherwise, the options specified in the CSS are used.
+
+```js
+postcss([
+    use({
+        modules: '*',
+        options: {
+            autoprefixer: {
+                browsers: ['> 1%', 'IE 7']
+            }
+        }
+    })
+]);
+```
+
 ## Usage
 
 See the [PostCSS documentation](https://github.com/postcss/postcss#usage) for

package.json

@@ -53,6 +53,7 @@
   "repository": "postcss/postcss-use",
   "dependencies": {
     "balanced-match": "^0.4.1",
+    "lodash.isplainobject": "^4.0.6",
     "postcss": "^5.0.21",
     "resolve-from": "^2.0.0"
   },

src/__tests__/fixtures/arrayOptions.css

@@ -0,0 +1,10 @@
+@use postcss-nobg(["background-repeat"]);
+
+.foo {
+    background-image: url(/foo.jpg);
+}
+
+.bar {
+    background: #bf1942;
+    background-repeat: no-repeat;
+}

src/__tests__/fixtures/options.css

@@ -0,0 +1,9 @@
+@use postcss-nobg(onlyImages: false);
+
+.foo {
+    background-image: url(/foo.jpg);
+}
+
+.bar {
+    background: #bf1942;
+}

src/__tests__/index.js

@@ -125,3 +125,52 @@ test('should not resolve plugins relative to CSS file by default', t => {
         t.deepEqual(err.message, `Cannot find module 'postcss-nobg'`);
     });
 });
+
+test('should be able to specify default options for plugins', t => {
+    const inputFile = path.join(__dirname, 'fixtures', 'test.css');
+    const outputFile = path.join(__dirname, 'fixtures', 'test.out.css');
+    const inputCss = fs.readFileSync(inputFile);
+    const options = {
+        nobg: {onlyImages: true},
+    };
+    return postcss(plugin({modules: '*', resolveFromFile: true, options})).process(inputCss, {
+        from: inputFile,
+        to: outputFile,
+    }).then(({css}) => {
+        const normalized = css.replace(/\s+/g, ' ').trim();
+        t.deepEqual(normalized, '.foo {background: blue;color: red;}', 'should remove only background image decls');
+    });
+});
+
+test('should be able to override default options', t => {
+    const inputFile = path.join(__dirname, 'fixtures', 'options.css');
+    const outputFile = path.join(__dirname, 'fixtures', 'options.out.css');
+    const inputCss = fs.readFileSync(inputFile);
+    const options = {
+        nobg: {onlyImages: true},
+    };
+    return postcss(plugin({modules: '*', resolveFromFile: true, options})).process(inputCss, {
+        from: inputFile,
+        to: outputFile,
+    }).then(({css}) => {
+        const normalized = css.replace(/\s+/g, ' ').trim();
+        t.deepEqual(normalized, '.foo { } .bar { }', 'should remove only background image decls');
+    });
+});
+
+test('should use specified options if specified options is not an object', t => {
+    const inputFile = path.join(__dirname, 'fixtures', 'arrayOptions.css');
+    const outputFile = path.join(__dirname, 'fixtures', 'arrayOptions.out.css');
+    const inputCss = fs.readFileSync(inputFile);
+    const options = {
+        nobg: {onlyImages: true},
+    };
+    return postcss(plugin({modules: '*', resolveFromFile: true, options})).process(inputCss, {
+        from: inputFile,
+        to: outputFile,
+    }).then(({css}) => {
+        const normalized = css.replace(/\s+/g, ' ').trim();
+        const expected = '.foo { background-image: url(/foo.jpg); } .bar { background: #bf1942; }';
+        t.deepEqual(normalized, expected, 'should remove only background-repeat decls');
+    });
+});

src/index.js

@@ -2,6 +2,7 @@ import path from 'path';
 import postcss from 'postcss';
 import balanced from 'balanced-match';
 import resolveFrom from 'resolve-from';
+import isPlainObject from 'lodash.isplainobject';
 
 const NAME = 'postcss-use';
 
@@ -31,6 +32,16 @@ function pluginOptsFromRule (rule) {
     return options;
 }
 
+function mergePluginOptions (plugin, defaultOpts, specifiedOpts) {
+    // Don't merge anything but objects
+    if (!isPlainObject(specifiedOpts) || !isPlainObject(defaultOpts)) {
+        return specifiedOpts;
+    }
+
+    // If both the default and specified options are plain objects, we can merge them
+    return {...defaultOpts, ...specifiedOpts};
+}
+
 export default postcss.plugin(NAME, (opts = {}) => {
     return (css, result) => {
         if (!opts.modules) {
@@ -88,7 +99,10 @@ export default postcss.plugin(NAME, (opts = {}) => {
                     throw new Error(`Cannot find module '${plugin}'`);
                 }
 
-                let instance = require(pluginPath)(pluginOpts);
+                let optsName = plugin.replace(/^postcss-/, '');
+                let defaultOpts = (opts.options && opts.options[optsName]) || {};
+                let mergedOptions = mergePluginOptions(optsName, defaultOpts, pluginOpts);
+                let instance = require(pluginPath)(mergedOptions);
                 if (instance.plugins) {
                     instance.plugins.forEach((p) => {
                         result.processor.plugins.push(p);