feat(rule): implement rule

.babelrc

@@ -0,0 +1,5 @@
+{
+  "presets": [
+    "es2015"
+  ]
+}

package.json

@@ -22,5 +22,16 @@
   "bugs": {
     "url": "https://github.com/azu/textlint-rule-max-comma/issues"
   },
-  "homepage": "https://github.com/azu/textlint-rule-max-comma#readme"
+  "homepage": "https://github.com/azu/textlint-rule-max-comma#readme",
+  "devDependencies": {
+    "babel-cli": "^6.7.7",
+    "babel-preset-es2015": "^6.6.0",
+    "babel-register": "^6.7.2",
+    "mocha": "^2.4.5",
+    "textlint-tester": "^1.2.0"
+  },
+  "dependencies": {
+    "sentence-splitter": "^2.0.0",
+    "unist-util-filter": "^0.2.1"
+  }
 }

src/textlint-rule-max-comma.js

@@ -1,14 +1,29 @@
 // LICENSE : MIT
 "use strict";
-const splitSentences = require("sentence-splitter").split;
-const Syntax = require("sentence-splitter").Syntax;
-module.exports = function (context) {
+import {split, Syntax as SentenceSyntax} from "sentence-splitter";
+const filter = require("unist-util-filter");
+function countOfComma(text) {
+    return text.split(",").length - 1;
+}
+const defaultOptions = {
+    // default: max comma count is 4
+    max: 4
+};
+module.exports = function (context, options = defaultOptions) {
+    const maxComma = options.max || defaultOptions.max;
     const {Syntax, RuleError, report, getSource} = context;
     return {
         [Syntax.Paragraph](node){
-            const text = getSource(node);
-            const sentences = splitSentences(text).filter(node => node.type === Syntax.Sentence)
+            const nodeWithoutCode = filter(node, (node) => node.type !== Syntax.Code);
+            const text = getSource(nodeWithoutCode);
+            const sentences = split(text).filter(node => node.type === SentenceSyntax.Sentence);
+            sentences.forEach(sentence => {
+                const sentenceValue = sentence.value;
+                const count = countOfComma(sentenceValue);
+                if(count > maxComma) {
+                    report(node, new RuleError(`This sentence exceeds the maximum count of comma. Maximum is ${maxComma}.`, sentence));
+                }
+            });
         }
-
     }
 };

test/mocha.opts

@@ -0,0 +1 @@
+--compilers js:babel-register

test/textlint-rule-max-comma-test.js

@@ -17,11 +17,14 @@ tester.run("no-todo", rule, {
     ],
     invalid: [
         {
-            text: "t0, t1, t2, t3, t4",
+            text: "t0, t1, t2, t3, t4, t5",
             errors: [
                 {
-                    message: " exceeds the maximum line length of"
+                    message: "This sentence exceeds the maximum count of comma. Maximum is 4.",
+                    line: 1,
+                    column: 1
                 }
             ]
-        }]
+        }
+    ]
 });