Add updateRules option

README.md

@@ -100,6 +100,34 @@ You can pass the path to a custom config file via the `configFile` option. The p
 }
 ```
 
+#### option.updateRules
+
+You can pass a function that can process all existing rules (user defined ones
+as well as the defaults that come from `sass-lint`).
+
+```javascript
+  // ...
+  .pipe(sassLint({
+    configFile: '.sass-lint.yml',
+    // all enabled rules will have the error severity
+    updateRules: (rules) => {
+      const isActiveRule = (x) => (typeof x === 'number' && x !== 0);
+
+      Object.keys(rules).forEach(r => {
+        if (isActiveRule(rules[r])) {
+          rules[r] = 2;
+        } else if (Array.isArray(rules[r])) {
+          if (isActiveRule(rules[r][0])) {
+            rules[r][0] = 2;
+          }
+        }
+      });
+
+      return rules;
+    }
+  }))
+```
+
 ### Example
 
 The following highlights all of the above options in use

index.js

@@ -42,6 +42,12 @@ var sassLint = function (options) {
     file.userOptions = userOptions;
     file.configFile = configFile;
 
+    // function that can modify all rules, including the default ones
+    if (options.updateRules) {
+      userOptions.rules = options.updateRules(file.sassConfig.rules);
+      delete options.updateRules;
+    }
+
     // lint the file and pass the user defined options and config path to sass lint to handle
     try {
       file.sassLint = [