Implement tslint enum-naming to enforce PascalCase on enum members (#1474)

6 files changed, 176 insertions, 3 deletions

diff --git a/packages/tslint-config/package.json b/packages/tslint-config/package.json
index 77c28f32c..cf39bde3e 100644
--- a/packages/tslint-config/package.json
+++ b/packages/tslint-config/package.json
@@ -9,6 +9,7 @@
     "scripts": {
         "build": "tsc -b",
         "build:ci": "yarn build",
+        "test": "mocha ./lib/test/*.spec.js",
         "clean": "shx rm -rf lib",
         "lint": "tslint --format stylish --project ."
     },
diff --git a/packages/tslint-config/rules/enumNamingRule.ts b/packages/tslint-config/rules/enumNamingRule.ts
new file mode 100644
index 000000000..56499618f
--- /dev/null
+++ b/packages/tslint-config/rules/enumNamingRule.ts
@@ -0,0 +1,60 @@
+import * as Lint from 'tslint';
+import * as ts from 'typescript';
+
+export class Rule extends Lint.Rules.AbstractRule {
+    public static FAILURE_STRING = `Enum member names should be PascalCase`;
+
+    public apply(sourceFile: ts.SourceFile): Lint.RuleFailure[] {
+        return this.applyWithFunction(sourceFile, walk);
+    }
+}
+
+function walk(ctx: Lint.WalkContext<void>): void {
+    // Recursively walk the AST starting with root node, `ctx.sourceFile`.
+    // Call the function `cb` (defined below) for each child.
+    return ts.forEachChild(ctx.sourceFile, cb);
+
+    function cb(node: ts.Node): void {
+        if (node.kind === ts.SyntaxKind.EnumMember) {
+            const keyNode = node.getFirstToken(ctx.sourceFile);
+            if (keyNode !== undefined) {
+                const keyText = keyNode.getText(ctx.sourceFile);
+                if (!isPascalCase(keyText)) {
+                    return ctx.addFailureAtNode(node, Rule.FAILURE_STRING, getFix(keyText, node));
+                }
+            }
+        }
+        // Continue recursion into the AST by calling function `cb` for every child of the current node.
+        return ts.forEachChild(node, cb);
+    }
+
+    function getFix(text: string, node: ts.Node): Lint.Replacement {
+        let fix = toPascalCase(text);
+        // check for `member = value`
+        if (node.getChildCount(ctx.sourceFile) === 3) {
+            const value = node.getLastToken(ctx.sourceFile);
+            if (value !== undefined) {
+                fix += ` = ${value.getText(ctx.sourceFile)}`;
+            }
+        }
+        return new Lint.Replacement(node.getStart(ctx.sourceFile), node.getWidth(ctx.sourceFile), fix);
+    }
+}
+
+// Modified from: https://github.com/jonschlinkert/pascalcase/
+function toPascalCase(str: string): string {
+    let result = str.replace(/([a-z0-9\W])([A-Z])/g, '$1 $2');
+    if (result.length === 1) {
+        return result.toUpperCase();
+    }
+    result = result.replace(/^[\W_\.]+|[\W_\.]+$/g, '').toLowerCase();
+    result = result.charAt(0).toUpperCase() + result.slice(1);
+    return result.replace(/[\W_\.]+(\w|$)/g, (_, ch) => {
+        return ch.toUpperCase();
+    });
+}
+function isPascalCase(s: string): boolean {
+    const regex = /^([A-Z0-9]+[a-z0-9]+)+$/g;
+    const key = s.split('=')[0].trim();
+    return regex.test(key);
+}
diff --git a/packages/tslint-config/test/enumNamingSpec.spec.ts b/packages/tslint-config/test/enumNamingSpec.spec.ts
new file mode 100644
index 000000000..d5b864eba
--- /dev/null
+++ b/packages/tslint-config/test/enumNamingSpec.spec.ts
@@ -0,0 +1,88 @@
+import * as assert from 'assert';
+
+import { Rule } from '../rules/enumNamingRule';
+
+import { getFixedResult, helper } from './lintrunner';
+const rule = 'enum-naming';
+
+describe('enumNamingRule', () => {
+    it(`should not fail PascalCase`, () => {
+        const src = `enum test { MemberOne, MemberTwo }`;
+        const result = helper(src, rule);
+        assert.equal(result.errorCount, 0);
+    });
+    it(`should not fail PascalCase keys with uncased values`, () => {
+        const src = `enum test { MemberOne = 'member_one', MemberTwo = 'member two' }`;
+        const result = helper(src, rule);
+        assert.equal(result.errorCount, 0);
+    });
+    it(`should not fail PascalCase keys with numbers`, () => {
+        const src = `enum test { Member1 = 'member_one', MemberTwo = 'member two' }`;
+        const result = helper(src, rule);
+        assert.equal(result.errorCount, 0);
+    });
+    it(`should fail with camelCase`, () => {
+        const src = `enum test { memberOne, memberTwo }`;
+        const result = helper(src, rule);
+        assert.equal(result.errorCount, 2);
+    });
+    it(`should fail with snake case`, () => {
+        const src = `enum test { member_one, member_two }`;
+        const result = helper(src, rule);
+        assert.equal(result.errorCount, 2);
+    });
+    it(`should fail with all caps`, () => {
+        const src = `enum test { MEMBERONE, MEMBER_TWO }`;
+        const result = helper(src, rule);
+        assert.equal(result.errorCount, 2);
+    });
+    it(`should fail with mixed case`, () => {
+        const src = `enum test { member_one, MemberTwo }`;
+        const result = helper(src, rule);
+        assert.equal(result.errorCount, 1);
+    });
+
+    it(`should fail with the right position`, () => {
+        const src = `enum test { MemberOne, member_two }`;
+        const startPosition = src.indexOf('member_two');
+        const endPosition = startPosition + 'member_two'.length;
+        const failure = helper(src, rule).failures[0];
+
+        assert.equal(failure.getStartPosition().getPosition(), startPosition);
+        assert.equal(failure.getEndPosition().getPosition(), endPosition);
+        assert.equal(failure.getFailure(), Rule.FAILURE_STRING);
+    });
+
+    it(`should fail with the right message`, () => {
+        const src = `enum test { memberOne, memberTwo }`;
+        const failure = helper(src, rule).failures[0];
+
+        assert.equal(failure.getFailure(), Rule.FAILURE_STRING);
+    });
+});
+describe('enumNaming fixer', () => {
+    it('should fix keys', () => {
+        const src = `enum test { MemberOne, memberTwo, member_three, MEMBER_FOUR, MEMBERFIVE }`;
+        const expected = `enum test { MemberOne, MemberTwo, MemberThree, MemberFour, Memberfive }`;
+        const actual = getFixedResult(src, rule);
+        const result = helper(src, rule);
+        assert.equal(result.errorCount, 4); // tslint:disable-line:custom-no-magic-numbers
+        assert.equal(actual, expected);
+    });
+    it('should not fix values', () => {
+        const src = `enum test { MemberOne = 'MemberOne', memberTwo = 'memberTwo', member_three = 'member_three', MEMBER_FOUR = 'MEMBER_FOUR' }`;
+        const expected = `enum test { MemberOne = 'MemberOne', MemberTwo = 'memberTwo', MemberThree = 'member_three', MemberFour = 'MEMBER_FOUR' }`;
+        const actual = getFixedResult(src, rule);
+        const result = helper(src, rule);
+        assert.equal(result.errorCount, 3); // tslint:disable-line:custom-no-magic-numbers
+        assert.equal(actual, expected);
+    });
+    it('should preserve values with equals sign', () => {
+        const src = `enum Operators { assign = '=', EQUALS = '==', Triple_Equals = '===' }`;
+        const expected = `enum Operators { Assign = '=', Equals = '==', TripleEquals = '===' }`;
+        const actual = getFixedResult(src, rule);
+        const result = helper(src, rule);
+        assert.equal(result.errorCount, 3); // tslint:disable-line:custom-no-magic-numbers
+        assert.equal(actual, expected);
+    });
+});
diff --git a/packages/tslint-config/test/lintrunner.ts b/packages/tslint-config/test/lintrunner.ts
new file mode 100644
index 000000000..fcd1b6844
--- /dev/null
+++ b/packages/tslint-config/test/lintrunner.ts
@@ -0,0 +1,23 @@
+import * as path from 'path';
+import { Configuration, Linter, Replacement } from 'tslint';
+
+export const helper = (src: string, rule: string) => {
+    const linter = new Linter({ fix: false });
+    linter.lint(
+        '',
+        src,
+        Configuration.parseConfigFile({
+            rules: {
+                [rule]: true,
+            },
+            rulesDirectory: path.join(__dirname, '../rules'),
+        }),
+    );
+    return linter.getResult();
+};
+
+export const getFixedResult = (src: string, rule: string) => {
+    const result = helper(src, rule);
+    const fixes = [].concat.apply(result.failures.map(x => x.getFix()));
+    return Replacement.applyFixes(src, fixes);
+};
diff --git a/packages/tslint-config/tsconfig.json b/packages/tslint-config/tsconfig.json
index 44845cf1f..b9a4dd03e 100644
--- a/packages/tslint-config/tsconfig.json
+++ b/packages/tslint-config/tsconfig.json
@@ -2,7 +2,7 @@
     "extends": "../../tsconfig",
     "compilerOptions": {
         "outDir": "lib",
-        "rootDir": "rules"
+        "rootDir": "."
     },
-    "include": ["./rules/**/*"]
+    "include": ["./rules/**/*", "test/**/*"]
 }
diff --git a/packages/tslint-config/tslint.json b/packages/tslint-config/tslint.json
index e8de6221e..a5fa6962c 100644
--- a/packages/tslint-config/tslint.json
+++ b/packages/tslint-config/tslint.json
@@ -25,6 +25,7 @@
         "curly": true,
         "custom-no-magic-numbers": [true, 0, 1, 2, 3, -1],
         "encoding": true,
+        "enum-naming": true,
         "eofline": true,
         "import-spacing": true,
         "indent": [true, "spaces", 4],
@@ -125,5 +126,5 @@
             "check-preblock"
         ]
     },
-    "rulesDirectory": "lib"
+    "rulesDirectory": "lib/rules"
 }