Merge pull request eslint#3154 from mysticatea/quotes/backtick-allows…

…-directive-prologue Fix: `quotes` with `"backtick"` allows directive prologues
soson · Jul 24, 2015 · 3f4b862 · 3f4b862
2 parents c73093a + 53a99d6
commit 3f4b862
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Showing 2 changed files with 72 additions and 2 deletions.
diff --git a/lib/rules/quotes.js b/lib/rules/quotes.js
@@ -29,6 +29,8 @@ var QUOTE_SETTINGS = {
 
 var AVOID_ESCAPE = "avoid-escape";
 
+var FUNCTION_TYPE = /^(?:Arrow)?Function(?:Declaration|Expression)$/;
+
 //------------------------------------------------------------------------------
 // Rule Definition
 //------------------------------------------------------------------------------
@@ -56,6 +58,53 @@ module.exports = function(context) {
         return node.type.indexOf("JSX") === 0;
     }
 
+    /**
+     * Checks whether or not a given node is a directive.
+     * The directive is a `ExpressionStatement` which has only a string literal.
+     * @param {ASTNode} node - A node to check.
+     * @returns {boolean} Whether or not the node is a directive.
+     * @private
+     */
+    function isDirective(node) {
+        return (
+            node.type === "ExpressionStatement" &&
+            node.expression.type === "Literal" &&
+            typeof node.expression.value === "string"
+        );
+    }
+
+    /**
+     * Checks whether or not a given node is a part of directive prologues.
+     * See also: http://www.ecma-international.org/ecma-262/6.0/#sec-directive-prologues-and-the-use-strict-directive
+     * @param {ASTNode} node - A node to check.
+     * @returns {boolean} Whether or not the node is a part of directive prologues.
+     * @private
+     */
+    function isPartOfDirectivePrologue(node) {
+        if (!isDirective(node.parent)) {
+            return false;
+        }
+
+        var block = node.parent.parent;
+        if (block.type !== "Program" && (block.type !== "BlockStatement" || !FUNCTION_TYPE.test(block.parent.type))) {
+            return false;
+        }
+
+        // Check the node is at a prologue.
+        for (var i = 0; i < block.body.length; ++i) {
+            var statement = block.body[i];
+
+            if (statement === node.parent) {
+                return true;
+            }
+            if (!isDirective(statement)) {
+                break;
+            }
+        }
+
+        return false;
+    }
+
     return {
 
         "Literal": function(node) {
@@ -67,7 +116,7 @@ module.exports = function(context) {
                 isValid;
 
             if (settings && typeof val === "string") {
-                isValid = isJSXElement(node.parent) || isSurroundedBy(rawVal, settings.quote);
+                isValid = (quoteOption === "backtick" && isPartOfDirectivePrologue(node)) || isJSXElement(node.parent) || isSurroundedBy(rawVal, settings.quote);
 
                 if (!isValid && avoidEscape) {
                     isValid = isSurroundedBy(rawVal, settings.alternateQuote) && rawVal.indexOf(settings.quote) >= 0;

diff --git a/tests/lib/rules/quotes.js b/tests/lib/rules/quotes.js
@@ -34,7 +34,14 @@ eslintTester.addRuleTest("lib/rules/quotes", {
         { code: "var foo = <div id=\"foo\"></div>;", args: [1, "backtick"], ecmaFeatures: { jsx: true } },
         { code: "var foo = <div>Hello world</div>;", args: [1, "backtick"], ecmaFeatures: { jsx: true }},
         { code: "var foo = `backtick`;", args: [1, "single"], ecmaFeatures: { templateStrings: true }},
-        { code: "var foo = `backtick`;", args: [1, "double"], ecmaFeatures: { templateStrings: true }}
+        { code: "var foo = `backtick`;", args: [1, "double"], ecmaFeatures: { templateStrings: true }},
+
+        // `backtick` should not warn the directive prologues.
+        { code: "\"use strict\"; var foo = `backtick`;", options: ["backtick"], ecmaFeatures: { templateStrings: true }},
+        { code: "\"use strict\"; 'use strong'; \"use asm\"; var foo = `backtick`;", options: ["backtick"], ecmaFeatures: { templateStrings: true }},
+        { code: "function foo() { \"use strict\"; \"use strong\"; \"use asm\"; var foo = `backtick`; }", options: ["backtick"], ecmaFeatures: { templateStrings: true }},
+        { code: "(function() { 'use strict'; 'use strong'; 'use asm'; var foo = `backtick`; })();", options: ["backtick"], ecmaFeatures: { templateStrings: true }},
+        { code: "(() => { \"use strict\"; \"use strong\"; \"use asm\"; var foo = `backtick`; })();", options: ["backtick"], ecmaFeatures: { arrowFunctions: true, templateStrings: true }}
     ],
     invalid: [
         { code: "var foo = 'bar';",
@@ -62,6 +69,20 @@ eslintTester.addRuleTest("lib/rules/quotes", {
           errors: [{ message: "Strings must use backtick.", type: "Literal" }]},
         { code: "var foo = 'bar';",
           args: [1, "backtick", "avoid-escape"],
+          errors: [{ message: "Strings must use backtick.", type: "Literal" }]},
+
+        // below are not the directive prologues.
+        { code: "var foo = `backtick`; \"use strict\";",
+          options: ["backtick"],
+          ecmaFeatures: { templateStrings: true },
+          errors: [{ message: "Strings must use backtick.", type: "Literal" }]},
+        { code: "{ \"use strict\"; var foo = `backtick`; }",
+          options: ["backtick"],
+          ecmaFeatures: { templateStrings: true },
+          errors: [{ message: "Strings must use backtick.", type: "Literal" }]},
+        { code: "if (1) { \"use strict\"; var foo = `backtick`; }",
+          options: ["backtick"],
+          ecmaFeatures: { templateStrings: true },
           errors: [{ message: "Strings must use backtick.", type: "Literal" }]}
     ]
 });