added inject option and tests

README.md

@@ -54,7 +54,8 @@ var files   = ['my', 'array', 'of', 'HTML', 'files', 'or', 'http://urls.com'],
         report       : false,
         banner       : false,
         uncssrc      : '.uncssrc',
-        userAgent    : 'Mozilla/5.0 (iPhone; CPU iPhone OS 10_3 like Mac OS X)'
+        userAgent    : 'Mozilla/5.0 (iPhone; CPU iPhone OS 10_3 like Mac OS X)',
+        inject       : function(window){ window.document.querySelector('html').classList.add('no-csscalc', 'csscalc'); }
     };
 
 uncss(files, options, function (error, output) {
@@ -103,6 +104,7 @@ Options:
   -u, --uncssrc <file>                  Load these options from <file>
   -n, --noBanner                        Disable banner
   -a, --userAgent <string>              Use a custom user agent string
+  -I, --inject <file>                   Path to javascript file to be executed before uncss runs
 ```
 
 **Note that you can pass both local file paths (which are processed by [glob](https://github.com/isaacs/node-glob)) and URLs to the program.**
@@ -159,6 +161,28 @@ Options:
   ```
 - **userAgent** (String): The user agent string that jsdom should send when requesting pages. May be useful when loading markup from services which use user agent based device detection to serve custom markup to mobile devices. Defaults to `uncss`.
 
+- **inject** (String / Function): Path to a local javascript file which is executed before uncss runs. A function can also be passed directly in.
+
+	Example inject.js file
+
+	```js
+	'use strict';
+
+	module.exports = function(window) {
+	    window.document.querySelector('html').classList.add('no-csscalc', 'csscalc');
+	};
+	```
+
+	Example of passing inject as a function
+
+	```js
+	{
+	  inject: function(window){
+	    window.document.querySelector('html').classList.add('no-csscalc', 'csscalc');
+	  }
+	}
+	```
+
 ### As a PostCSS Plugin
 
 UnCSS can be used as a [PostCSS](https://github.com/postcss/postcss) Plugin.

bin/uncss

@@ -30,6 +30,7 @@
         .option('-u, --uncssrc <file>', 'Load these options from <file>')
         .option('-n, --noBanner', 'Disable banner')
         .option('-a, --userAgent <string>', 'Use a custom useragent string')
+        .option('-I, --inject <file>', 'Path to javascript file to be executed before uncss runs')
         .parse(process.argv);
 
     options = {
@@ -43,7 +44,8 @@
         htmlroot: program.htmlroot,
         uncssrc: program.uncssrc,
         banner: !program.noBanner,
-        userAgent: program.userAgent
+        userAgent: program.userAgent,
+        inject: program.inject
     };
 
     if (program.args.length) {

src/jsdom.js

@@ -35,6 +35,16 @@ function fromSource(src, options) {
         };
     }
 
+    if (options.inject) {
+        config.onload = function(window) {
+            if (typeof options.inject === 'function') {
+                options.inject(window);
+            } else {
+                require(path.join(__dirname, options.inject))(window);
+            }
+        };
+    }
+
     return new Promise((resolve, reject) => {
         jsdom.env(src, config, (err, res) => {
             if (err) {

src/uncss.js

@@ -203,7 +203,8 @@ function init(files, options, callback) {
         banner: true,
         // gulp-uncss parameters:
         raw: null,
-        userAgent: 'uncss'
+        userAgent: 'uncss',
+        inject: null
     });
 
     process(options).then(([css, report]) => callback(null, css, report), callback);

tests/jsdom.js

@@ -103,4 +103,34 @@ describe('jsdom', () => {
             done();
         });
     });
+
+    it('Should execute passed in javascript function before uncss runs', (done) => {
+        const options = {
+            htmlroot: path.join(__dirname, './jsdom'),
+            inject: (window) => {
+                window.document.querySelector('html').classList.add('no-test', 'test');
+            }
+        };
+        uncss(['tests/jsdom/inject.html'], options, (err, output) => {
+            expect(err).to.equal(null);
+            expect(output).to.include('.no-test .inject');
+            expect(output).to.include('.test .inject');
+
+            done();
+        });
+    });
+
+    it('Should load then execute passed in javascript function before uncss runs', (done) => {
+        const options = {
+            htmlroot: path.join(__dirname, './jsdom'),
+            inject: '../tests/jsdom/inject.js'
+        };
+        uncss(['tests/jsdom/inject.html'], options, (err, output) => {
+            expect(err).to.equal(null);
+            expect(output).to.include('.no-test .inject');
+            expect(output).to.include('.test .inject');
+
+            done();
+        });
+    });
 });

tests/jsdom/inject.html

@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html lang="en">
+    <head>
+        <meta charset="utf-8">
+        <title>jsdom inject test</title>
+        <link rel="stylesheet" href="jsdom.css">
+    </head>
+    <body>
+        <div class="inject"></div>
+    </body>
+</html>

tests/jsdom/inject.js

@@ -0,0 +1,5 @@
+'use strict';
+
+module.exports = function(window) {
+    window.document.querySelector('html').classList.add('no-test', 'test');
+};

tests/jsdom/jsdom.css

@@ -21,3 +21,11 @@
 .error {
   margin: 0;
 }
+
+.no-test .inject{
+	margin: 0;
+}
+
+.test .inject{
+	margin: 0;
+}