Rule to prevent certain keywords being used as variable names

README.md

@@ -172,6 +172,7 @@ A sample configuration file with all options is available [here](https://github.
 * `no-eval` disallows `eval` function invocations.
 * `no-inferrable-types` disallows explicit type declarations for variables or parameters initialized to a number, string, or boolean
 * `no-internal-module` disallows internal `module`, use `namespace` instead.
+* `no-keyword-named-variables` disallows the use of certain TypeScript keywords (`any`, `Number`, `number`, `String`, `string`, `Boolean`, `boolean`, `undefined`) as variable or parameter names
 * `no-require-imports` disallows require() style imports
 * `no-string-literal` disallows object access via string literals.
 * `no-switch-case-fall-through` disallows falling through case statements.

docs/sample.tslint.json

@@ -1,52 +1,64 @@
 {
   "rules": {
-  "align": [true,
-        "parameters",
-        "arguments",
-        "statements"],
+    "align": [
+      true,
+      "parameters",
+      "arguments",
+      "statements"
+    ],
     "ban": false,
     "class-name": true,
-    "comment-format": [true,
-        "check-space",
-        "check-lowercase"
+    "comment-format": [
+      true,
+      "check-space",
+      "check-lowercase"
     ],
     "curly": true,
     "eofline": true,
     "forin": true,
-    "indent": [true, "spaces"],
+    "indent": [
+      true,
+      "spaces"
+    ],
     "interface-name": true,
     "jsdoc-format": true,
     "label-position": true,
     "label-undefined": true,
-    "max-line-length": [true, 140],
+    "max-line-length": [
+      true,
+      140
+    ],
     "member-access": true,
-    "member-ordering": [true,
-        "public-before-private",
-        "static-before-instance",
-        "variables-before-functions"
+    "member-ordering": [
+      true,
+      "public-before-private",
+      "static-before-instance",
+      "variables-before-functions"
     ],
     "no-any": false,
     "no-arg": true,
     "no-bitwise": true,
     "no-conditional-assignment": true,
-    "no-console": [true,
-        "debug",
-        "info",
-        "time",
-        "timeEnd",
-        "trace"
+    "no-console": [
+      true,
+      "debug",
+      "info",
+      "time",
+      "timeEnd",
+      "trace"
     ],
     "no-construct": true,
     "no-constructor-vars": true,
     "no-debugger": true,
     "no-duplicate-key": true,
-    "no-shadowed-variable": true,
     "no-duplicate-variable": true,
     "no-empty": true,
     "no-eval": true,
     "no-inferrable-types": false,
     "no-internal-module": true,
+    "no-keyword-named-variables": true,
     "no-require-imports": true,
+    "no-shadowed-variable": true,
     "no-string-literal": true,
     "no-switch-case-fall-through": true,
     "no-trailing-whitespace": true,
@@ -57,46 +69,63 @@
     "no-var-keyword": true,
     "no-var-requires": true,
     "object-literal-sort-keys": true,
-    "one-line": [true,
-        "check-open-brace",
-        "check-catch",
-        "check-else",
-        "check-whitespace"
+    "one-line": [
+      true,
+      "check-open-brace",
+      "check-catch",
+      "check-else",
+      "check-whitespace"
+    ],
+    "quotemark": [
+      true,
+      "double",
+      "avoid-escape"
     ],
-    "quotemark": [true, "double", "avoid-escape"],
     "radix": true,
     "semicolon": true,
     "switch-default": true,
-    "trailing-comma": [true, {
+    "trailing-comma": [
+      true,
+      {
         "multiline": "always",
         "singleline": "never"
-    }],
-    "triple-equals": [true, "allow-null-check"],
-    "typedef": [true,
-        "call-signature",
-        "parameter",
-        "property-declaration",
-        "variable-declaration",
-        "member-variable-declaration"
+      }
+    ],
+    "triple-equals": [
+      true,
+      "allow-null-check"
     ],
-    "typedef-whitespace": [true, {
+    "typedef": [
+      true,
+      "call-signature",
+      "parameter",
+      "property-declaration",
+      "variable-declaration",
+      "member-variable-declaration"
+    ],
+    "typedef-whitespace": [
+      true,
+      {
         "call-signature": "nospace",
         "index-signature": "nospace",
         "parameter": "nospace",
         "property-declaration": "nospace",
         "variable-declaration": "nospace"
-    }],
-    "use-strict": [true,
-        "check-module",
-        "check-function"
+      }
+    ],
+    "use-strict": [
+      true,
+      "check-module",
+      "check-function"
     ],
     "variable-name": false,
-    "whitespace": [true,
-        "check-branch",
-        "check-decl",
-        "check-operator",
-        "check-separator",
-        "check-type"
+    "whitespace": [
+      true,
+      "check-branch",
+      "check-decl",
+      "check-operator",
+      "check-separator",
+      "check-type"
     ]
   }
 }

src/rules/noKeywordNamedVariablesRule.ts

@@ -0,0 +1,58 @@
+/*
+ * Copyright 2014 Palantir Technologies, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+import * as Lint from "../lint";
+import * as ts from "typescript";
+
+const BAD_NAMES = [ "any", "Number", "number", "String", "string", "Boolean", "boolean", "undefined" ];
+
+export class Rule extends Lint.Rules.AbstractRule {
+    public static FAILURE_STRING = "variable name clashes with keyword/type: ";
+
+    public apply(sourceFile: ts.SourceFile): Lint.RuleFailure[] {
+        return this.applyWithWalker(new NoKeywordNamedVariablesWalker(sourceFile, this.getOptions()));
+    }
+}
+
+class NoKeywordNamedVariablesWalker extends Lint.RuleWalker {
+    public visitBindingElement(node: ts.BindingElement) {
+        if (node.name.kind === ts.SyntaxKind.Identifier) {
+            this.handleVariableName(<ts.Identifier> node.name);
+        }
+        super.visitBindingElement(node);
+    }
+
+    public visitParameterDeclaration(node: ts.ParameterDeclaration) {
+        if (node.name.kind === ts.SyntaxKind.Identifier) {
+            this.handleVariableName(<ts.Identifier> node.name);
+        }
+        super.visitParameterDeclaration(node);
+    }
+
+    public visitVariableDeclaration(node: ts.VariableDeclaration) {
+        if (node.name.kind === ts.SyntaxKind.Identifier) {
+            this.handleVariableName(<ts.Identifier> node.name);
+        }
+        super.visitVariableDeclaration(node);
+    }
+
+    private handleVariableName(name: ts.Identifier) {
+        const variableName = name.text;
+
+        if(BAD_NAMES.indexOf(variableName) !== -1) {
+            this.addFailure(this.createFailure(name.getStart(), name.getWidth(), Rule.FAILURE_STRING));
+        }
+    }
+}

src/tsconfig.json

@@ -32,15 +32,16 @@
         "./rules/noConditionalAssignmentRule.ts",
         "./rules/noConsecutiveBlankLinesRule.ts",
         "./rules/noConsoleRule.ts",
-        "./rules/noConstructRule.ts",
         "./rules/noConstructorVarsRule.ts",
+        "./rules/noConstructRule.ts",
         "./rules/noDebuggerRule.ts",
         "./rules/noDuplicateKeyRule.ts",
         "./rules/noDuplicateVariableRule.ts",
         "./rules/noEmptyRule.ts",
         "./rules/noEvalRule.ts",
         "./rules/noInferrableTypesRule.ts",
         "./rules/noInternalModuleRule.ts",
+        "./rules/noKeywordNamedVariablesRule",
         "./rules/noRequireImportsRule.ts",
         "./rules/noShadowedVariableRule.ts",
         "./rules/noStringLiteralRule.ts",

test/files/rules/nokeywordnamedvariables_1.test.ts

@@ -0,0 +1,23 @@
+let any = 1;
+let Number = 2;
+let number = 3;
+let String = 4;
+let string = 5;
+let Boolean = 6;
+let boolean = 7;
+let undefined = 8;
+
+let Any = 1;
+let anyName = 2;
+let NumbeR = 3
+let NumberEg = 4;
+let numbeR = 5;
+let numberEg = 6;
+let StrinG = 7;
+let StringEg = 8;
+let BooleaN = 9;
+let BooleanEg = 10;
+let booleaN = 11;
+let booleanEg = 12;
+let undefineD = 13;
+let undefinedEg = 14;

test/files/rules/nokeywordnamedvariables_2.test.ts

@@ -0,0 +1,8 @@
+let any: any;
+let Number: Number;
+let number: number;
+let String: String;
+let string: string;
+let Boolean: Boolean;
+let boolean: boolean;
+let undefined: any;

test/files/rules/nokeywordnamedvariables_3.test.ts

@@ -0,0 +1,17 @@
+function F1(any) {}
+function F2(Number) {}
+function F3(number) {}
+function F4(String) {}
+function F5(string) {}
+function F6(Boolean) {}
+function F7(boolean) {}
+function F8(undefined) {}
+
+function G1(any: any) {}
+function G2(Number: Number) {}
+function G3(number: number) {}
+function G4(String: String) {}
+function G5(string: string) {}
+function G6(Boolean: Boolean) {}
+function G7(boolean: boolean) {}
+function G8(undefined: any) {}

test/files/rules/nokeywordnamedvariables_4.test.ts

@@ -0,0 +1,8 @@
+let [ any ] = [ 1 ];
+let [ Number ] = [ 2 ];
+let [ number ] = [ 3 ];
+let [ String ] = [ 4 ];
+let [ string ] = [ 5 ];
+let [ Boolean ] = [ 6 ];
+let [ boolean ] = [ 7 ];
+let [ undefined ] = [ 8 ];

test/files/rules/nokeywordnamedvariables_5.test.ts

@@ -0,0 +1,8 @@
+let { any } = { any: 1 };
+let { Number } = { Number: 1 };
+let { number } = { number: 1 };
+let { String } = { String: 1 };
+let { string } = { string: 1 };
+let { Boolean } = { Boolean: 1 };
+let { boolean } = { boolean: 1 };
+let { undefined } = { undefined: 1 };