rule no-invalid-xpath: add other tests

lib/rules/no-invalid-xpath.js

@@ -4,6 +4,9 @@
 // or ts-xpath: https://www.npmjs.com/package/ts-xpath
 
 const jsXpath = require("js-xpath")
+const XPathAnalyzer = require("xpath-analyzer").default;
+const isEqual = require('lodash.isequal');
+const bcp47Validate = require("bcp47-validate").validate
 
 // https://developer.mozilla.org/fr/docs/Web/API/XPathResult#Constants
 const XPathResult = {
@@ -20,31 +23,84 @@ const XPathResult = {
 }
 
 const create = context => {
+	const parseXpath = xpathExpression => {
+		new XPathAnalyzer(xpathExpression);
+		// other librairy
+		jsXpath.parse(xpathExpression)
+	}
+
+	const isValidXPath = xpathExpression => {
+		var bool
+		try {
+			parseXpath(xpathExpression)
+			bool = true
+		} catch {
+			bool = false
+		}
+		return bool
+	}
+
 	return {
 		'CallExpression[callee.object.name=\'document\'][callee.property.name=\'evaluate\'][arguments.length > 0]': node => {
 			const xpathExpression = node.arguments[0].value
 
 			if (xpathExpression.length > 100) {
 				context.report({node, message: "large XPath expression detected"})
 			}
-			
+
 			try {
 				//	select([], xpathExpression)
+
 				jsXpath.parse(xpathExpression)
 			} catch (error) {
 				//	//TODO: add xpath value
-				//	console.log(error)
+					//console.log(error)
 				context.report({node, message: "invalid XPath: " + "Unrecognized text"})
 				return;
 			} 
 
 			const parsed = jsXpath.parse(xpathExpression)
-			var regenerated = parsed.toXPath();
+			const regenerated = parsed.toXPath();
 			if (xpathExpression !== regenerated) {
 				context.report({node, message: "XPath expression lisibility: " + regenerated})
 			}
 
-			// an other rule:
+			try {
+				var analyzer = new XPathAnalyzer(xpathExpression);
+				var obj = analyzer.parse();
+			} catch (error) {
+				context.report({node, message: "invalid XPath"})
+				return;
+			}
+			var analyzer = new XPathAnalyzer(xpathExpression);
+			var obj = analyzer.parse();
+			if (obj.steps && obj.steps.length >= 2 && obj.steps[1].predicates) {
+				const predicates = obj.steps[1].predicates
+				if (predicates.length >= 2 && isEqual(predicates[1], predicates[0])) {
+					context.report({node, message: "XPath expression: duplicate predicate"})
+				}
+			}
+
+			// other rule:
+			for (step in obj.steps) {
+				var step = obj.steps[step]
+				try {
+				const name = step.predicates[0].lhs.steps[0].test.name
+				if (name == "lang") {
+					const lang = step.predicates[0].rhs.string
+					if (bcp47Validate(lang) == false) {
+						context.report({node, message: "invalid @lang: " + lang})
+					}
+				}
+				} catch (error) {
+					if (error.name !== 'TypeError') {
+						console.error("Message: ", error.message);
+					}
+				}
+			}
+
+
+			// TODO: create an other rule no-magic-number-about-xpath (by moving code)
 
 			if (node.arguments.length >= 4) {
 				if (node.arguments[3].type == 'Literal') {

package.json

@@ -25,14 +25,17 @@
   "dependencies": {
     "@types/eslint": "^4.16.6",
     "@types/listr": "^0.13.0",
+    "bcp47-validate": "^1.0.0",
     "execa": "^1.0.0",
     "import-modules": "^1.1.0",
     "is-url": "^1.2.4",
     "js-xpath": "0.0.4",
     "listr": "^0.14.3",
+    "lodash.isequal": "^4.5.0",
     "reflect-type-3": "^1.0.0",
     "requireindex": "~1.1.0",
     "tempy": "^0.2.1",
+    "xpath-analyzer": "^3.0.0",
     "xpath.js": "^1.1.0"
   },
   "devDependencies": {

tests/lib/rules/no-invalid-xpath.js

@@ -33,10 +33,66 @@ ruleTester.run("no-invalid-xpath", rule, {
       },
       {
         code: "document.evaluate(\"count(//div)\", document)",
-      }
+      },
+      {
+        code: "document.evaluate(\"//some/xpath/statement[@coolness = very]\", document)",
+      },
+      {
+        code: "document.evaluate(\"//title[@lang = \'en\']\", document)",
+      },
+      {
+        code: "document.evaluate(\"//title[@lang = \'en-GB\']\", document)",
+      },
+      {
+        code: "document.evaluate(\"//*[@lang = \'en-GB\']\", document)",
+      },
+      // XPath utility function, function isn't part of JavaScript itself, it is just a utility that's available in the console
+      {
+        code: "$x('//html', document)",
+      },
+      {
+        code: "window.document.evaluate(\"//html\", document)",
+      },
     ],
 
     invalid: [
+        {
+          code: "document.evaluate(\"//title[@lang = 'invalid-lang:']\", document)",
+          errors: [{
+              message: "invalid @lang: invalid-lang:",
+          }]
+        },
+        {
+          code: "document.evaluate(\"//title/book[@lang = 'invalid-lang:']\", document)",
+          errors: [{
+              message: "invalid @lang: invalid-lang:",
+          }]
+        },
+        {
+          code: "document.evaluate(\"//\", document)",
+          errors: [{
+              message: "invalid XPath: Unrecognized text",
+          }]
+        },
+        {
+          code: "document.evaluate(\"\", document)",
+          errors: [{
+              message: "invalid XPath: Unrecognized text",
+          }]
+        },
+        {
+          code: "document.evaluate(\"//book[]\", document)",
+          errors: [{
+              message: "invalid XPath: Unrecognized text",
+          }]
+        },
+        // no error in Chrome but not a valid XPath expression:
+        {
+          code: "document.evaluate(\"/html[callee.object.name]\", document)",
+          errors: [{
+            message: "invalid XPath",
+        }]
+        },
         {
             code:  "document.evaluate(\"/html/body//h2:llL ms%dl\", document)",
             errors: [{
@@ -59,6 +115,9 @@ ruleTester.run("no-invalid-xpath", rule, {
           code: "document.evaluate(\"//article[count(author) = 1][count(author) = 1][count(author) = 1][count(author) = 1][count(author) = 1][count(author) = 1][count(author) = 1][count(author) = 1][count(author) = 1][count(author) = 1][count(author) = 1][count(author) = 1][count(author) = 1][count(author) = 1][count(author) = 1]/title\", document)",
           errors: [{
               message: 'large XPath expression detected',
+          },
+          {
+            message: 'XPath expression: duplicate predicate',
           }]
       },
     ]