[#2829] add autofix for number-no-trailing-zeros

lib/rules/number-no-trailing-zeros/README.md

@@ -8,6 +8,8 @@ a { top: 0.5000px; bottom: 1.0px; }
  *        These trailing zeros */
 ```
 
+The `--fix` option on the [command line](../../../docs/user-guide/cli.md#autofixing-errors) can automatically fix some of the problems reported by this rule.
+
 ## Options
 
 ### `true`

lib/rules/number-no-trailing-zeros/__tests__/index.js

@@ -9,7 +9,7 @@ const rule = rules[ruleName];
 testRule(rule, {
   ruleName,
   config: [true],
-
+  fix: true,
   accept: [
     {
       code: "a { padding: 1px; }"
@@ -73,66 +73,70 @@ testRule(rule, {
   reject: [
     {
       code: "a { padding: 1.0px; }",
+      fixed: "a { padding: 1px; }",
       message: messages.rejected,
       line: 1,
       column: 16
     },
     {
       code: "a { padding: 1.000px; }",
+      fixed: "a { padding: 1px; }",
       message: messages.rejected,
       line: 1,
-      column: 18
+      column: 16
     },
     {
       code: "a { padding: 10.0px; }",
+      fixed: "a { padding: 10px; }",
       message: messages.rejected,
       line: 1,
       column: 17
     },
     {
       code: "a { padding: 10.010px; }",
-      message: messages.rejected,
-      line: 1,
-      column: 19
-    },
-    {
-      code: "a { padding: 10.010px; }",
+      fixed: "a { padding: 10.01px; }",
       message: messages.rejected,
       line: 1,
       column: 19
     },
     {
       code: "a { padding: 0.010px; }",
+      fixed: "a { padding: 0.01px; }",
       message: messages.rejected,
       line: 1,
       column: 18
     },
     {
       code: "a { padding: .010px; }",
+      fixed: "a { padding: .01px; }",
       message: messages.rejected,
       line: 1,
       column: 17
     },
     {
       code: "a { transform: translate(2px, 0.40px); }",
+      fixed: "a { transform: translate(2px, 0.4px); }",
       message: messages.rejected,
       line: 1,
       column: 34
     },
     {
       code: "a { padding: 10px 1px 10.010px 3.00003em; }",
+      fixed: "a { padding: 10px 1px 10.01px 3.00003em; }",
       message: messages.rejected,
       line: 1,
       column: 28
     },
     {
       code: "a { padding: 10px 1px 10.01px 3.000030em; }",
+      fixed: "a { padding: 10px 1px 10.01px 3.00003em; }",
       message: messages.rejected,
       line: 1,
       column: 38
     },
     {
       code: "@media (min-width: 100.0px) {}",
+      fixed: "@media (min-width: 100px) {}",
       message: messages.rejected,
       line: 1,
       column: 24

lib/rules/number-no-trailing-zeros/index.js

@@ -13,7 +13,7 @@ const messages = ruleMessages(ruleName, {
   rejected: "Unexpected trailing zero(s)"
 });
 
-const rule = function(actual) {
+const rule = function(actual, secondary, context) {
   return (root, result) => {
     const validOptions = validateOptions(result, ruleName, { actual });
     if (!validOptions) {
@@ -31,6 +31,8 @@ const rule = function(actual) {
     root.walkDecls(decl => check(decl, decl.value, declarationValueIndex));
 
     function check(node, value, getIndex) {
+      const fixPositions = [];
+
       // Get out quickly if there are no periods
       if (value.indexOf(".") === -1) {
         return;
@@ -50,28 +52,69 @@ const rule = function(actual) {
           return;
         }
 
-        const match = /(\.\d*)0+(?:\D|$)/.exec(valueNode.value);
-
+        const match = /\.(\d*?)(0+)(?:\D|$)/.exec(valueNode.value);
+        // match[1] is any numbers between the decimal and our trailing zero, could be empty
+        // match[2] is our trailing zero(s)
         if (match === null) {
           return;
         }
 
-        report({
-          message: messages.rejected,
-          node,
-          index:
-            getIndex(node) +
-            valueNode.sourceIndex +
-            match.index +
-            match[1].length,
-          result,
-          ruleName
-        });
+        // our index is:
+        //  the index of our valueNode +
+        //  the index of our match +
+        //  1 for our decimal +
+        //  the length of our potential non-zero number match (match[1])
+        const index = valueNode.sourceIndex + match.index + 1 + match[1].length;
+
+        // our startIndex is identical to our index except when we have only
+        // trailing zeros after our decimal. in that case we don't need the decimal
+        // either so we move our index back by 1.
+        const startIndex = match[1].length > 0 ? index : index - 1;
+
+        // our end index is our original index + the length of our trailing zeros
+        const endIndex = index + match[2].length;
+
+        if (context.fix) {
+          fixPositions.unshift({
+            startIndex,
+            endIndex
+          });
+          return;
+        } else {
+          report({
+            message: messages.rejected,
+            node,
+            // this is the index of the _first_ trailing zero
+            index: getIndex(node) + index,
+            result,
+            ruleName
+          });
+        }
       });
+
+      if (fixPositions.length) {
+        fixPositions.forEach(function(fixPosition) {
+          const startIndex = fixPosition.startIndex;
+          const endIndex = fixPosition.endIndex;
+          if (node.type === "atrule") {
+            node.params = removeTrailingZeros(
+              node.params,
+              startIndex,
+              endIndex
+            );
+          } else {
+            node.value = removeTrailingZeros(node.value, startIndex, endIndex);
+          }
+        });
+      }
     }
   };
 };
 
+function removeTrailingZeros(input, startIndex, endIndex) {
+  return input.slice(0, startIndex) + input.slice(endIndex);
+}
+
 rule.ruleName = ruleName;
 rule.messages = messages;
 module.exports = rule;