[FIX][no-use-before-define] cleanup logic (#202)

This PR changes logic behind `no-use-before-define` to traverse all scopes

fixes: #141

lib/rules/no-use-before-define.js

@@ -268,49 +268,14 @@ module.exports = {
                     data: reference.identifier,
                 });
             });
-        }
 
-        /**
-         * Validates variables inside of a node's scope.
-         * @param {ASTNode} node The node to check.
-         * @returns {void}
-         * @private
-         */
-        function findVariables() {
-            const scope = context.getScope();
-
-            findVariablesInScope(scope);
+            scope.childScopes.forEach(findVariablesInScope);
         }
 
-        const ruleDefinition = {
-            "Program:exit"(node) {
-                const scope = context.getScope(),
-                    ecmaFeatures = context.parserOptions.ecmaFeatures || {};
-
-                findVariablesInScope(scope);
-
-                // both Node.js and Modules have an extra scope
-                if (ecmaFeatures.globalReturn || node.sourceType === "module") {
-                    findVariablesInScope(scope.childScopes[0]);
-                }
+        return {
+            Program() {
+                findVariablesInScope(context.getScope());
             },
         };
-
-        if (context.parserOptions.ecmaVersion >= 6) {
-            ruleDefinition["BlockStatement:exit"] = findVariables;
-            ruleDefinition["SwitchStatement:exit"] = findVariables;
-
-            ruleDefinition["ArrowFunctionExpression:exit"] = function(node) {
-                if (node.body.type !== "BlockStatement") {
-                    findVariables();
-                }
-            };
-        } else {
-            ruleDefinition["FunctionExpression:exit"] = findVariables;
-            ruleDefinition["FunctionDeclaration:exit"] = findVariables;
-            ruleDefinition["ArrowFunctionExpression:exit"] = findVariables;
-        }
-
-        return ruleDefinition;
     },
 };

tests/lib/rules/no-use-before-define.js

@@ -17,14 +17,18 @@ const rule = require("../../../lib/rules/no-use-before-define"),
 // Tests
 //------------------------------------------------------------------------------
 
-const ruleTester = new RuleTester();
+const ruleTester = new RuleTester({
+    parser: "typescript-eslint-parser",
+});
 
 ruleTester.run("no-use-before-define", rule, {
     valid: [
         "var a=10; alert(a);",
         "function b(a) { alert(a); }",
         "Object.hasOwnProperty.call(a);",
         "function a() { alert(arguments);}",
+        "declare function a()",
+        "declare class a { foo() }",
         {
             code: `
 a();
@@ -177,7 +181,6 @@ var x: Foo = 2;
 type Foo = string | number
             `,
             options: [{ typedefs: false }],
-            parser: "typescript-eslint-parser",
         },
 
         // test for https://github.com/bradzacher/eslint-plugin-typescript/issues/142
@@ -199,6 +202,26 @@ export class Test {}
             parserOptions: { ecmaVersion: 6, sourceType: "module" },
             options: [{ classes: false }],
         },
+        // https://github.com/bradzacher/eslint-plugin-typescript/issues/141
+        {
+            code: `
+interface ITest {
+  first : boolean;
+  second : string;
+  third : boolean;
+}
+
+let first = () => console.log('first');
+
+export let second = () => console.log('second');
+
+export namespace Third {
+  export let third = () => console.log('third');
+}
+            `,
+            parserOptions: { ecmaVersion: 6, sourceType: "module" },
+            parser: "typescript-eslint-parser",
+        },
     ],
     invalid: [
         {
@@ -337,6 +360,7 @@ a();
     function a() {}
 }
             `,
+            parser: "espree",
             errors: [
                 {
                     message: "'a' was used before it was defined.",