Fixes #80: Support ESLint's flat configuration format

.eslintrc

@@ -17,5 +17,13 @@
       "bracketSpacing": false
     }],
     "no-console": "error"
-  }
+  },
+  "overrides": [
+    {
+      "files": "*.mjs",
+      "parserOptions": {
+        "sourceType": "module"
+      }
+    }
+  ]
 }

.github/workflows/node.js.yml

@@ -29,8 +29,8 @@ jobs:
     - run: npm ci
     - run: npm run lint
     - run: npm run test
-    - run: npm run integration ci 7 8 # eslint versions
-    - run: npm run integration test 7 8 # eslint versions
+    - run: npm run integration ci 7-legacy 8-legacy 8 # eslint versions
+    - run: npm run integration test 7-legacy 8-legacy 8 # eslint versions
     - name: Upload coverage to Codecov
       uses: codecov/codecov-action@v2
       with:

README.md

@@ -24,15 +24,31 @@ $ yarn add --dev eslint eslint-plugin-json
 
 ## Usage
 
-### Basic configuration
+### Basic configuration (Flat Config ESLint Format)
 
 The `json` plugin ship with two recommended config you can use to easily activate it via the `extends` key.
 It comes in two flavor: one strict (`recommended`) and one allowing comments `recommended-with-comments`.
 
 
+```js
+{
+    export default [
+      {
+        files: ["**/*.json"],
+        ...json.configs["recommended"],
+    ];
+}
+```
+
+### Basic configuration (Legacy ESLint Format)
+
+The `json` plugin ship with two recommended config you can use to easily activate it via the `extends` key.
+It comes in two flavor: one strict (`recommended-legacy`) and one allowing comments `recommended-with-comments-legacy`.
+
+
 ```json
 {
-    "extends": ["plugin:json/recommended"]
+    "extends": ["plugin:json/recommended-legacy"]
 }
 ```
 
@@ -43,14 +59,45 @@ eslint . --ext .json,.js
 eslint example.json
 ```
 
-### Custom Configuration
+### Custom Configuration (Flat Config ESLint Format)
+
+If you want more granular control over which rules, and which severity you want.
 
-If you want more granular control over which rules, and wich severity you want
+If you want them all, add the `json/json` rule (or its alias `json/*`). (this is what the `recommended` config does)
+
+#### Global rules
+The global rules (`json/json` or its alias `json/*`) activate all the rules.
+Note it can be configured to ignore errors cause by comments.
+To do so, add option `'allowComments'` or `{allowComments: true}`
+
+For instance:
+```js
+{
+    import json from "eslint-plugin-json";
+
+    export default [
+      {
+        files: ["**/*.json"],
+        plugins: { json },
+        processor: "json/json"
+        "rules": {
+          "json/*": ["error", "allowComments"],
+          // or the equivalent:
+          "json/*": ["error", {"allowComments": true}]
+        }
+      },
+    ];
+}
+```
+
+### Custom Configuration (Legacy ESLint Format)
+
+If you want more granular control over which rules, and which severity you want.
 
 Add `json` to the list of plugins (You can omit the `eslint-plugin-` prefix)
 Then pick your rules.
 
-If you want them all, add the `json/json` rule (or its alias `json/*`). (this is what the `recommended` config does)
+If you want them all, add the `json/json` rule (or its alias `json/*`). (this is what the `recommended-legacy` config does)
 
 #### Global rules
 The global rules (`json/json` or its alias `json/*`) activate all the rules.

src/index.js

@@ -104,65 +104,98 @@ const errorSignature = (err) =>
 
 const getErrorCode = _.pipe(_.get('ruleId'), _.split('/'), _.last);
 
-const processors = {
-    '.json': {
-        preprocess: function (text, fileName) {
-            const textDocument = jsonService.TextDocument.create(fileName, 'json', 1, text);
-            fileDocuments[fileName] = textDocument;
-            const parsed = jsonServiceHandle.parseJSONDocument(textDocument);
-            fileLintResults[fileName] = getDiagnostics(parsed);
-            fileComments[fileName] = parsed.comments;
-            return ['']; // sorry nothing ;)
-        },
-        postprocess: function (messages, fileName) {
-            const textDocument = fileDocuments[fileName];
-            delete fileLintResults[fileName];
-            delete fileComments[fileName];
-            return _.pipe(
-                _.first,
-                _.groupBy(errorSignature),
-                _.mapValues((errors) => {
-                    if (errors.length === 1) return _.first(errors);
-                    // Otherwise there is two errors: the generic and specific one
-                    // json/* or json/json and json/some-code
-                    const firstErrorCode = getErrorCode(errors[0]);
-                    const isFirstGeneric = ['*', 'json'].includes(firstErrorCode);
-                    const genericError = errors[isFirstGeneric ? 0 : 1];
-                    const specificError = errors[isFirstGeneric ? 1 : 0];
-                    return genericError.severity > specificError.severity
-                        ? genericError
-                        : specificError;
-                }),
-                _.mapValues((error) => {
-                    const source = textDocument.getText({
-                        start: {line: error.line - 1, character: error.column},
-                        end: {line: error.endLine - 1, character: error.endColumn},
-                    });
-                    return _.assign(error, {
-                        source,
-                        column: error.column + 1,
-                        endColumn: error.endColumn + 1,
-                    });
-                }),
-                _.values
-            )(messages);
-        },
+const meta = {
+    name: 'eslint-plugin-json',
+    version: '3.1.0',
+};
+
+const jsonProcessor = {
+    preprocess: function (text, fileName) {
+        const textDocument = jsonService.TextDocument.create(fileName, 'json', 1, text);
+        fileDocuments[fileName] = textDocument;
+        const parsed = jsonServiceHandle.parseJSONDocument(textDocument);
+        fileLintResults[fileName] = getDiagnostics(parsed);
+        fileComments[fileName] = parsed.comments;
+        return ['']; // sorry nothing ;)
     },
+    postprocess: function (messages, fileName) {
+        const textDocument = fileDocuments[fileName];
+        delete fileLintResults[fileName];
+        delete fileComments[fileName];
+        return _.pipe(
+            _.first,
+            _.groupBy(errorSignature),
+            _.mapValues((errors) => {
+                if (errors.length === 1) return _.first(errors);
+                // Otherwise there is two errors: the generic and specific one
+                // json/* or json/json and json/some-code
+                const firstErrorCode = getErrorCode(errors[0]);
+                const isFirstGeneric = ['*', 'json'].includes(firstErrorCode);
+                const genericError = errors[isFirstGeneric ? 0 : 1];
+                const specificError = errors[isFirstGeneric ? 1 : 0];
+                return genericError.severity > specificError.severity
+                    ? genericError
+                    : specificError;
+            }),
+            _.mapValues((error) => {
+                const source = textDocument.getText({
+                    start: {line: error.line - 1, character: error.column},
+                    end: {line: error.endLine - 1, character: error.endColumn},
+                });
+                return _.assign(error, {
+                    source,
+                    column: error.column + 1,
+                    endColumn: error.endColumn + 1,
+                });
+            }),
+            _.values
+        )(messages);
+    },
+};
+
+const processors = {
+    // Supports old config.
+    '.json': jsonProcessor,
+    // Supports new config.
+    json: jsonProcessor,
 };
 
 const configs = {
-    recommended: {
+    'recommended-legacy': {
         plugins: ['json'],
         rules: {
             'json/*': 'error',
         },
     },
-    'recommended-with-comments': {
+    'recommended-with-comments-legacy': {
         plugins: ['json'],
         rules: {
             'json/*': ['error', {allowComments: true}],
         },
     },
 };
 
-module.exports = {rules, configs, processors};
+const json = {meta, rules, configs, processors};
+
+json.configs['recommended'] = {
+    files: ['**/*.json'],
+    plugins: {
+        json,
+    },
+    rules: {
+        'json/*': 'error',
+    },
+    processor: 'json/json',
+};
+json.configs['recommended-with-comments'] = {
+    files: ['**/*.json'],
+    plugins: {
+        json,
+    },
+    rules: {
+        'json/*': ['error', {allowComments: true}],
+    },
+    processor: 'json/json',
+};
+
+module.exports = json;

test/.eslintrc.with-recommended-comments-config.mjs

@@ -0,0 +1,3 @@
+import json from '../src/index.js';
+
+export default [json.configs['recommended-with-comments']];

test/.eslintrc.with-recommended-comments-legacy-config.json

@@ -0,0 +1,3 @@
+{
+  "extends": ["plugin:self/recommended-with-comments-legacy"]
+}

test/.eslintrc.with-recommended-config.mjs

@@ -0,0 +1,3 @@
+import json from '../src/index.js';
+
+export default [json.configs['recommended']];

test/.eslintrc.with-recommended-legacy-config.json

@@ -0,0 +1,3 @@
+{
+    "extends": ["plugin:self/recommended-legacy"]
+}

test/custom.eslintrc.config.mjs

@@ -0,0 +1,28 @@
+import json from '../src/index.js';
+
+export default [
+    {
+        files: ['**/*.json'],
+        plugins: {json},
+        processor: 'json/json',
+        rules: {
+            'json/*': 'warn',
+            'json/duplicate-key': 'error',
+            'json/trailing-comma': 'error',
+        },
+    },
+    {
+        files: ['samples/json-with-comments.json'],
+        plugins: {json},
+        rules: {
+            'json/*': ['warn', {allowComments: true}],
+        },
+    },
+    {
+        files: ['samples/wrong-syntax.json'],
+        plugins: {json},
+        rules: {
+            'json/*': 'error',
+        },
+    },
+];