chore(*): Enable comma-dangle (#271)

As per the discussion on slack.
Enable `comma-dangle` eslint rule + prettier config.
Good for two reasons:
1) (the main reason) It will create less noise in PRs:
```diff
 {
-  "foo": true
+  "foo": true,
+  "bar": false
 }
```
2) It makes reordering members easier because there is always a comma at the end.

----

Steps to create this PR:
1) add line in eslint config
2) add prettier config
3) run `yarn format`
4) ???
5) profit.

No other code was manually touched in the making of this PR.

.eslintignore

@@ -2,6 +2,7 @@ node_modules
 dist
 jest.config.js
 fixtures
+shared-fixtures
 coverage
 
 packages/typescript-estree/src/estree

.eslintrc.json

@@ -7,6 +7,7 @@
   },
   "extends": ["eslint:recommended", "plugin:@typescript-eslint/recommended"],
   "rules": {
+    "comma-dangle": ["error", "always-multiline"],
     "no-mixed-operators": "error",
     "no-console": "off",
     "no-undef": "off",

.prettierignore

@@ -5,4 +5,5 @@
 **/tests/integration/fixtures/**/*
 **/lib/configs/recommended.json
 **/.vscode
-**/.nyc_output
+**/.nyc_output
+packages/eslint-plugin-tslint/tests/test-tslint-rules-directory/alwaysFailRule.js

.prettierrc

@@ -0,0 +1,3 @@
+{
+  "trailingComma": "all"
+}

packages/eslint-plugin-tslint/jest.config.js

@@ -3,11 +3,11 @@
 module.exports = {
   testEnvironment: 'node',
   transform: {
-    '^.+\\.tsx?$': 'ts-jest'
+    '^.+\\.tsx?$': 'ts-jest',
   },
   testRegex: './tests/.+\\.spec\\.ts$',
   collectCoverage: false,
   collectCoverageFrom: ['src/**/*.{js,jsx,ts,tsx}'],
   moduleFileExtensions: ['ts', 'tsx', 'js', 'jsx', 'json', 'node'],
-  coverageReporters: ['text-summary', 'lcov']
+  coverageReporters: ['text-summary', 'lcov'],
 };

packages/eslint-plugin-tslint/src/index.ts

@@ -30,20 +30,20 @@ const tslintConfig = memoize(
   (
     lintFile: string,
     tslintRules: RawRulesConfig,
-    tslintRulesDirectory: string[]
+    tslintRulesDirectory: string[],
   ) => {
     if (lintFile != null) {
       return Configuration.loadConfigurationFromPath(lintFile);
     }
     return Configuration.parseConfigFile({
       rules: tslintRules || {},
-      rulesDirectory: tslintRulesDirectory || []
+      rulesDirectory: tslintRulesDirectory || [],
     });
   },
   (lintFile: string | undefined, tslintRules = {}, tslintRulesDirectory = []) =>
     `${lintFile}_${Object.keys(tslintRules).join(',')}_${
       tslintRulesDirectory.length
-    }`
+    }`,
 );
 
 export const rules = {
@@ -56,7 +56,7 @@ export const rules = {
       docs: {
         description:
           'Wraps a TSLint configuration and lints the whole source using TSLint',
-        category: 'TSLint'
+        category: 'TSLint',
       },
       schema: [
         {
@@ -67,21 +67,21 @@ export const rules = {
               /**
                * No fixed schema properties for rules, as this would be a permanently moving target
                */
-              additionalProperties: true
+              additionalProperties: true,
             },
             rulesDirectory: {
               type: 'array',
               items: {
-                type: 'string'
-              }
+                type: 'string',
+              },
             },
             lintFile: {
-              type: 'string'
-            }
+              type: 'string',
+            },
           },
-          additionalProperties: false
-        }
-      ]
+          additionalProperties: false,
+        },
+      ],
     },
     create: function(context: Rule.RuleContext) {
       const fileName = context.getFilename();
@@ -94,7 +94,7 @@ export const rules = {
        */
       if (!parserServices || !parserServices.program) {
         throw new Error(
-          `You must provide a value for the "parserOptions.project" property for @typescript-eslint/parser`
+          `You must provide a value for the "parserOptions.project" property for @typescript-eslint/parser`,
         );
       }
 
@@ -104,7 +104,7 @@ export const rules = {
       const {
         rules: tslintRules,
         rulesDirectory: tslintRulesDirectory,
-        lintFile
+        lintFile,
       } = context.options[0];
 
       const program: Program = parserServices.program;
@@ -116,13 +116,13 @@ export const rules = {
        */
       const tslintOptions = {
         formatter: 'json',
-        fix: false
+        fix: false,
       };
       const tslint = new CustomLinter(tslintOptions, program);
       const configuration = tslintConfig(
         lintFile,
         tslintRules,
-        tslintRulesDirectory
+        tslintRulesDirectory,
       );
       tslint.lint(fileName, sourceCode, configuration);
 
@@ -140,13 +140,13 @@ export const rules = {
             loc: {
               start: {
                 line: start.line + 1,
-                column: start.character
+                column: start.character,
               },
               end: {
                 line: end.line + 1,
-                column: end.character
-              }
-            }
+                column: end.character,
+              },
+            },
           });
         });
       }
@@ -155,6 +155,6 @@ export const rules = {
        * Return an empty object for the ESLint rule
        */
       return {};
-    }
-  }
+    },
+  },
 };

packages/eslint-plugin-tslint/tests/index.spec.ts

@@ -11,18 +11,18 @@ const ruleTester = new RuleTester({
      * Project is needed to generate the parserServices
      * within @typescript-eslint/parser
      */
-    project: './tests/tsconfig.json'
+    project: './tests/tsconfig.json',
   },
-  parser: '@typescript-eslint/parser'
+  parser: '@typescript-eslint/parser',
 });
 
 /**
  * Inline rules should be supported
  */
 const tslintRulesConfig = {
   rules: {
-    semicolon: [true, 'always']
-  }
+    semicolon: [true, 'always'],
+  },
 };
 
 /**
@@ -32,36 +32,36 @@ const tslintRulesDirectoryConfig = {
   rulesDirectory: ['./tests/test-tslint-rules-directory'],
   rules: {
     'always-fail': {
-      severity: 'error'
-    }
-  }
+      severity: 'error',
+    },
+  },
 };
 
 ruleTester.run('tslint/config', rules.config, {
   valid: [
     {
       code: 'var foo = true;',
-      options: [tslintRulesConfig]
+      options: [tslintRulesConfig],
     },
     {
       filename: './tests/test-project/file-spec.ts',
       code: readFileSync('./tests/test-project/file-spec.ts', 'utf8').replace(
         /\n/g,
-        ' '
+        ' ',
       ),
       parserOptions: {
-        project: `${__dirname}/test-project/tsconfig.json`
+        project: `${__dirname}/test-project/tsconfig.json`,
       },
       options: [
         {
-          ...tslintRulesConfig
-        }
-      ]
+          ...tslintRulesConfig,
+        },
+      ],
     },
     {
       code: 'throw "should be ok because rule is not loaded";',
-      options: [tslintRulesConfig]
-    }
+      options: [tslintRulesConfig],
+    },
   ],
 
   invalid: [
@@ -71,9 +71,9 @@ ruleTester.run('tslint/config', rules.config, {
       errors: [
         {
           message:
-            'Throwing plain strings (not instances of Error) gives no stack traces (tslint:no-string-throw)'
-        }
-      ]
+            'Throwing plain strings (not instances of Error) gives no stack traces (tslint:no-string-throw)',
+        },
+      ],
     },
     {
       code: 'var foo = true // semicolon',
@@ -83,9 +83,9 @@ ruleTester.run('tslint/config', rules.config, {
         {
           message: 'Missing semicolon (tslint:semicolon)',
           line: 1,
-          column: 15
-        }
-      ]
+          column: 15,
+        },
+      ],
     },
     {
       code: 'var foo = true // fail',
@@ -95,33 +95,33 @@ ruleTester.run('tslint/config', rules.config, {
         {
           message: 'failure (tslint:always-fail)',
           line: 1,
-          column: 1
-        }
-      ]
+          column: 1,
+        },
+      ],
     },
     {
       filename: './tests/test-project/source.ts',
       code: readFileSync('./tests/test-project/source.ts', 'utf8').replace(
         /\n/g,
-        ' '
+        ' ',
       ),
       parserOptions: {
-        project: `${__dirname}/test-project/tsconfig.json`
+        project: `${__dirname}/test-project/tsconfig.json`,
       },
       options: [
         {
           rulesDirectory: [
-            `${__dirname}/../../../node_modules/tslint/lib/rules`
+            `${__dirname}/../../../node_modules/tslint/lib/rules`,
           ],
-          rules: { 'restrict-plus-operands': true }
-        }
+          rules: { 'restrict-plus-operands': true },
+        },
       ],
       errors: [
         {
           message:
-            "Operands of '+' operation must either be both strings or both numbers, consider using template literals (tslint:restrict-plus-operands)"
-        }
-      ]
-    }
-  ]
+            "Operands of '+' operation must either be both strings or both numbers, consider using template literals (tslint:restrict-plus-operands)",
+        },
+      ],
+    },
+  ],
 });

packages/eslint-plugin-tslint/tests/test-tslint-rules-directory/alwaysFailRule.js

@@ -1,3 +1,4 @@
+
 const Lint = require('tslint');
 
 class Rule extends Lint.Rules.AbstractRule {

packages/eslint-plugin/docs/rules/camelcase.md

@@ -68,7 +68,7 @@ function foo({ no_camelcased = 'default value' }) {
 }
 
 var obj = {
-  my_pref: 1
+  my_pref: 1,
 };
 
 var { category_id = 1 } = query;
@@ -125,7 +125,7 @@ Examples of **correct** code for this rule with the `{ "properties": "never" }`
 /*eslint @typescript-eslint/camelcase: ["error", {properties: "never"}]*/
 
 var obj = {
-  my_pref: 1
+  my_pref: 1,
 };
 ```
 

packages/eslint-plugin/docs/rules/no-extraneous-class.md

@@ -42,7 +42,7 @@ const StaticOnly = {
   version: 42,
   hello() {
     console.log('Hello, world!');
-  }
+  },
 };
 ```
 

packages/eslint-plugin/docs/rules/no-this-alias.md

@@ -45,9 +45,9 @@ You can pass an object option:
     'error',
     {
       allowDestructuring: true, // Allow `const { props, state } = this`; false by default
-      allowedNames: ['self'] // Allow `const self = this`; `[]` by default
-    }
-  ]
+      allowedNames: ['self'], // Allow `const self = this`; `[]` by default
+    },
+  ],
 }
 ```
 

packages/eslint-plugin/docs/rules/no-unnecessary-qualifier.md

@@ -24,7 +24,7 @@ namespace A {
 ```ts
 enum A {
   B,
-  C = A.B
+  C = A.B,
 }
 ```
 
@@ -52,11 +52,11 @@ namespace Y {
 ```ts
 enum A {
   X,
-  Y
+  Y,
 }
 
 enum B {
-  Z = A.X
+  Z = A.X,
 }
 ```
 

packages/eslint-plugin/docs/rules/no-unused-vars.md

@@ -63,7 +63,7 @@ alert(x);
 myFunc(
   function foo() {
     // ...
-  }.bind(this)
+  }.bind(this),
 );
 
 (function(foo) {