Add ignoreUnits option to number-max-precision rule

lib/rules/number-max-precision/README.md

@@ -37,3 +37,57 @@ a { top: 3.24px; }
 ```css
 @media (min-width: 3.23em) {}
 ```
+
+## Optional secondary options
+
+### `ignoreUnits: ["/regex/", "string"]`
+
+Ignore the precision of numbers for values with the specified units.
+
+For example, with `2`.
+
+Given:
+
+```js
+["/^my-/", "%"]
+```
+
+The following patterns are considered violations:
+
+```css
+a { top: 3.245px; }
+```
+
+```css
+a { top: 3.245634px; }
+```
+
+```css
+@media (min-width: 3.234em) {}
+```
+
+The following patterns are *not* considered violations:
+
+```css
+a { top: 3.245%; }
+```
+
+```css
+@media (min-width: 3.23em) {}
+```
+
+```css
+a {
+  width: 10.5432%;
+}
+```
+
+```css
+a { top: 3.245my-unit; }
+```
+
+```css
+a {
+  width: 10.989my-other-unit;
+}
+```

lib/rules/number-max-precision/__tests__/index.js

@@ -150,3 +150,59 @@ testRule(rule, {
     }
   ]
 });
+
+testRule(rule, {
+  ruleName,
+  config: [0, { ignoreUnits: ["%", "/^my-/"] }],
+
+  accept: [
+    {
+      code: "a { top: 3%; }"
+    },
+    {
+      code: "a { top: 3.1%; }"
+    },
+    {
+      code: "a { top: 3.123456%; }"
+    },
+    {
+      code: "a { top: 3px; }"
+    },
+    {
+      code: "a { color: #ff00; }"
+    },
+    {
+      code: "a { padding: 6.123% 3.1234%; }"
+    },
+    {
+      code: "a { top: 3.245my-unit; }"
+    }
+  ],
+
+  reject: [
+    {
+      code: "a { top: 3.1px; }",
+      message: messages.expected(3.1, 0),
+      line: 1,
+      column: 10
+    },
+    {
+      code: "a { top: 3.123em; }",
+      message: messages.expected(3.123, 0),
+      line: 1,
+      column: 10
+    },
+    {
+      code: "a { padding: 6.123px 3.1234px; }",
+      message: messages.expected(6.123, 0),
+      line: 1,
+      column: 14
+    },
+    {
+      code: "a { top: 6.123other-unit; }",
+      message: messages.expected(6.123, 0),
+      line: 1,
+      column: 10
+    }
+  ]
+});

lib/rules/number-max-precision/index.js

@@ -2,6 +2,8 @@
 
 const atRuleParamIndex = require("../../utils/atRuleParamIndex");
 const declarationValueIndex = require("../../utils/declarationValueIndex");
+const getUnitFromValueNode = require("../../utils/getUnitFromValueNode");
+const optionsMatches = require("../../utils/optionsMatches");
 const report = require("../../utils/report");
 const ruleMessages = require("../../utils/ruleMessages");
 const validateOptions = require("../../utils/validateOptions");
@@ -16,12 +18,23 @@ const messages = ruleMessages(ruleName, {
     `Expected "${number}" to be "${number.toFixed(precision)}"`
 });
 
-const rule = function(precision) {
+const rule = function(precision, options) {
   return (root, result) => {
-    const validOptions = validateOptions(result, ruleName, {
-      actual: precision,
-      possible: [_.isNumber]
-    });
+    const validOptions = validateOptions(
+      result,
+      ruleName,
+      {
+        actual: precision,
+        possible: [_.isNumber]
+      },
+      {
+        optional: true,
+        actual: options,
+        possible: {
+          ignoreUnits: [_.isString]
+        }
+      }
+    );
     if (!validOptions) {
       return;
     }
@@ -43,6 +56,12 @@ const rule = function(precision) {
       }
 
       valueParser(value).walk(valueNode => {
+        const unit = getUnitFromValueNode(valueNode);
+
+        if (optionsMatches(options, "ignoreUnits", unit)) {
+          return;
+        }
+
         // Ignore `url` function
         if (
           valueNode.type === "function" &&