void-0-rule

README.md

@@ -722,6 +722,15 @@ We recommend you specify exact versions of lint libraries, including `tslint-mic
       </td>
       <td>4.0.2</td>
     </tr>
+    <tr>
+      <td>
+        <code>void-zero</code>
+      </td>
+      <td>
+        <code>void 0</code>, which resolves to <code>undefined</code>, can be confusing to newcomers. Exclusively use <code>undefined</code> to reduce ambiguity.
+      </td>
+      <td>6.1.0</td>
+    </tr>
     <tr>
       <td>
         <code>no-var-self</code>

recommended_ruleset.js

@@ -181,6 +181,7 @@ module.exports = {
         'unified-signatures': true,
         'use-default-type-parameter': true,
         'variable-name': true,
+        'void-zero': true,
 
         /**
          * Accessibility. The following rules should be turned on to guarantee the best user

src/voidZeroRule.ts

@@ -0,0 +1,47 @@
+import * as ts from 'typescript';
+import * as Lint from 'tslint';
+import * as tsutils from 'tsutils';
+
+import { ExtendedMetadata } from './utils/ExtendedMetadata';
+
+const FAILURE_STRING: string = 'Replace void 0 with undefined';
+
+export class Rule extends Lint.Rules.AbstractRule {
+    public static metadata: ExtendedMetadata = {
+        ruleName: 'void-zero',
+        type: 'maintainability',
+        description: 'Avoid using void 0; use undefined instead.',
+        hasFix: true,
+        rationale: 'void 0, which resolves to undefined, can be confusing to newcomers. Exclusively use undefined to reduce ambiguity.',
+        options: null, // tslint:disable-line:no-null-keyword
+        optionsDescription: '',
+        typescriptOnly: true,
+        issueClass: 'Non-SDL',
+        issueType: 'Warning',
+        severity: 'Low',
+        level: 'Opportunity for Excellence',
+        group: 'Clarity',
+        commonWeaknessEnumeration: '480'
+    };
+
+    public apply(sourceFile: ts.SourceFile): Lint.RuleFailure[] {
+        return this.applyWithFunction(sourceFile, walk);
+    }
+}
+
+function walk(ctx: Lint.WalkContext<void>) {
+    function cb(node: ts.Node): void {
+        if (tsutils.isVoidExpression(node)) {
+            if (node.expression !== undefined && node.expression.getText() === '0') {
+                const nodeStart = node.getStart();
+                const nodeWidth = node.getWidth();
+                const fix = new Lint.Replacement(nodeStart, nodeWidth, 'undefined');
+
+                ctx.addFailureAt(nodeStart, nodeWidth, FAILURE_STRING, fix);
+            }
+        }
+        return ts.forEachChild(node, cb);
+    }
+
+    return ts.forEachChild(ctx.sourceFile, cb);
+}

tests/void-zero/test.ts.fix

@@ -0,0 +1,22 @@
+new Array(undefined);
+function mockFunction(arg1: undefined, arg2: string) {}
+mockFunction(undefined, 'arg2String')
+const bar = undefined;
+const foo = {
+    bar: undefined,
+};
+class MockClass {
+    private foo = undefined
+    static bar = undefined
+}
+
+new Array(undefined);
+mockFunction(undefined, 'arg2String')
+const bar = undefined;
+const foo = {
+    bar: undefined,
+};
+class MockClass {
+    private foo = undefined
+    static bar = undefined
+}

tests/void-zero/test.ts.lint

@@ -0,0 +1,28 @@
+new Array(undefined);
+function mockFunction(arg1: undefined, arg2: string) {}
+mockFunction(undefined, 'arg2String')
+const bar = undefined;
+const foo = {
+    bar: undefined,
+};
+class MockClass {
+    private foo = undefined
+    static bar = undefined
+}
+
+new Array(void 0);
+          ~~~~~~ [Replace void 0 with undefined]
+mockFunction(void 0, 'arg2String')
+             ~~~~~~ [Replace void 0 with undefined]
+const bar = void 0;
+            ~~~~~~ [Replace void 0 with undefined]
+const foo = {
+    bar: void 0,
+         ~~~~~~ [Replace void 0 with undefined]
+};
+class MockClass {
+    private foo = void 0
+                  ~~~~~~ [Replace void 0 with undefined]
+    static bar = void 0
+                 ~~~~~~ [Replace void 0 with undefined]
+}

tests/void-zero/tslint.json

@@ -0,0 +1,5 @@
+{
+    "rules": {
+        "void-zero": true
+    }
+}

tslint-warnings.csv

@@ -319,5 +319,6 @@ use-simple-attributes,Enforce usage of only simple attribute types.,TSLINT1PG0L9
 valid-typeof,Ensures that the results of typeof are compared against a valid string.,TSLINT1IB59P1,tslint,Non-SDL,Error,Critical,Opportunity for Excellence,See description on the tslint or tslint-microsoft-contrib website,TSLint Procedure,,
 variable-name,Checks variable names for various errors.,TSLINT1CIV7K3,tslint,Non-SDL,Warning,Important,Opportunity for Excellence,See description on the tslint or tslint-microsoft-contrib website,TSLint Procedure,"398, 710","CWE 398 - Indicator of Poor Code Quality
 CWE 710 - Coding Standards Violation"
+void-zero,Avoid using void 0; use undefined instead.,TSLINT1BDGNG2,tslint,Non-SDL,Warning,Low,Opportunity for Excellence,See description on the tslint or tslint-microsoft-contrib website,TSLint Procedure,480,"CWE 480 - Use of Incorrect Operator"
 whitespace,Enforces whitespace style conventions.,TSLINTC35UUS,tslint,Non-SDL,Warning,Low,Opportunity for Excellence,See description on the tslint or tslint-microsoft-contrib website,TSLint Procedure,"398, 710","CWE 398 - Indicator of Poor Code Quality
 CWE 710 - Coding Standards Violation"

tslint.json

@@ -148,6 +148,7 @@
         "switch-final-break": true,
         "type-literal-delimiter": false,
         "underscore-consistent-invocation": true,
+        "void-zero": true,
         "use-default-type-parameter": false,
         "use-named-parameter": true,
         "use-simple-attributes": true,