Update ESLint to v9 (#1394)

Co-authored-by: Muffin <[email protected]>

.prettierignore

@@ -2,7 +2,7 @@ build
 images
 licenses
 website
-.eslintrc.js
+eslint.config.js
 *.json
 *.yml
 *.md

eslint.config.js

@@ -0,0 +1,205 @@
+const js = require('@eslint/js');
+const globals = require('globals');
+
+module.exports = [
+  // Base on eslint recommended
+  js.configs.recommended,
+
+  // Common for all files
+  {
+    languageOptions: {
+      ecmaVersion: 2022,
+      sourceType: 'commonjs'
+    },
+    rules: {
+      // Unused variables commonly indicate logic errors
+      'no-unused-vars': [
+        'error',
+        {
+          // Unused arguments are useful, eg. it can be nice for blocks to accept `args` even if they don't use it
+          args: 'none',
+          // Allow silently eating try { } catch (e) { }
+          caughtErrors: 'none',
+          // Variables starting with _ are intentionally unused
+          argsIgnorePattern: '^_',
+          varsIgnorePattern: '^_',
+        }
+      ],
+      // Allow while (true) { }
+      'no-constant-condition': [
+        'error',
+        {
+          checkLoops: false
+        }
+      ],
+      // Allow empty catch {} blocks
+      'no-empty': [
+        'error',
+        {
+          allowEmptyCatch: true
+        }
+      ],
+      // Returning a value from a constructor() implies a mistake
+      'no-constructor-return': 'error',
+      // new Promise(async () => {}) implies a mistake
+      'no-async-promise-executor': 'warn',
+      // x === x implies a mistake
+      'no-self-compare': 'error',
+      // Using ${...} in a non-template-string implies a mistake
+      'no-template-curly-in-string': 'error',
+      // Loops that only iterate once imply a mistake
+      'no-unreachable-loop': 'error',
+      // Detect some untrusted code execution
+      'no-eval': 'error',
+      'no-implied-eval': 'error',
+      'no-new-func': 'error',
+      'no-script-url': 'error',
+      // Combinations of || and && are unreadable and may not do what you expect
+      'no-mixed-operators': [
+        'error',
+        {
+          groups: [
+            ['&&', '||']
+          ]
+        }
+      ],
+      // Disallow async functions that don't need to be. This is important as a Promise and non-Promise return value
+      // significantly impacts the behavior of projects.
+      'require-await': 'error'
+    }
+  },
+
+  // For development server
+  {
+    files: [
+      'development/**'
+    ],
+    languageOptions: {
+      globals: {
+        ...globals.commonjs,
+        ...globals.node
+      }
+    }
+  },
+
+  // For extensions
+  {
+    files: [
+      'extensions/**'
+    ],
+    languageOptions: {
+      globals: {
+        ...globals.browser,
+        Blockly: 'readonly',
+        Scratch: 'readonly',
+        ScratchBlocks: 'readonly',
+        ScratchExtensions: 'readonly',
+        scaffolding: 'readonly'
+      }
+    },
+    rules: {
+      // Require each extension to use strict mode
+      'strict': ['error', 'function'],
+      // Disallow APIs that are replaced by Scratch.* APIs
+      // This is not comprehensive, but it should be enough to prevent the most common ways for these to be written.
+      'no-restricted-globals': [
+        'error',
+        {
+          name: 'vm',
+          message: 'Use Scratch.vm instead of the global vm object. You also can use const vm = Scratch.vm;'
+        }
+      ],
+      'no-restricted-syntax': [
+        'error',
+        {
+          selector: 'CallExpression[callee.name=fetch]',
+          message: 'Use Scratch.fetch() instead of fetch()'
+        },
+        {
+          selector: 'CallExpression[callee.object.name=window][callee.property.name=fetch]',
+          message: 'Use Scratch.fetch() instead of window.fetch()'
+        },
+        {
+          selector: 'CallExpression[callee.name=open]',
+          message: 'Use Scratch.openWindow() instead of open()'
+        },
+        {
+          selector: 'CallExpression[callee.object.name=window][callee.property.name=open]',
+          message: 'Use Scratch.openWindow() instead of window.open()'
+        },
+        {
+          selector: 'AssignmentExpression[left.object.name=location][left.property.name=href]',
+          message: 'Use Scratch.redirect() instead of location.href = ...'
+        },
+        {
+          selector: 'AssignmentExpression[left.object.object.name=window][left.object.property.name=location][left.property.name=href]',
+          message: 'Use Scratch.redirect() instead of window.location.href = ...'
+        },
+        {
+          selector: 'AssignmentExpression[left.name=location]',
+          message: 'Use Scratch.redirect() instead of location = ...'
+        },
+        {
+          selector: 'AssignmentExpression[left.object.name=window][left.property.name=location]',
+          message: 'Use Scratch.redirect() instead of window.location = ...'
+        },
+        {
+          selector: 'CallExpression[callee.object.name=location][callee.property.name=assign]',
+          message: 'Use Scratch.redirect() instead of location.assign()'
+        },
+        {
+          selector: 'CallExpression[callee.object.object.name=window][callee.object.property.name=location][callee.property.name=assign]',
+          message: 'Use Scratch.redirect() instead of window.location.assign()'
+        },
+        {
+          selector: 'CallExpression[callee.object.name=location][callee.property.name=replace]',
+          message: 'Use Scratch.redirect() instead of location.replace()'
+        },
+        {
+          selector: 'CallExpression[callee.object.object.name=window][callee.object.property.name=location][callee.property.name=replace]',
+          message: 'Use Scratch.redirect() instead of window.location.replace()'
+        },
+        {
+          selector: 'NewExpression[callee.name=XMLHttpRequest]',
+          message: 'Use Scratch.fetch() instead of XMLHttpRequest'
+        },
+        {
+          selector: 'NewExpression[callee.name=WebSocket]',
+          message: 'Ensure that `await Scratch.canFetch(url)` is checked first, then add // eslint-disable-next-line no-restricted-syntax'
+        },
+        {
+          selector: 'NewExpression[callee.name=Image]',
+          message: 'Ensure that `await Scratch.canFetch(url)` is checked first, then add // eslint-disable-next-line no-restricted-syntax'
+        },
+        {
+          selector: 'NewExpression[callee.name=Audio]',
+          message: 'Ensure that `await Scratch.canFetch(url)` is checked first, then add // eslint-disable-next-line no-restricted-syntax'
+        },
+        {
+          selector: 'Program > :not(ExpressionStatement[expression.type=CallExpression][expression.callee.type=/FunctionExpression/])',
+          message: 'All extension code must be within (function (Scratch) { ... })(Scratch);'
+        },
+        {
+          selector: 'CallExpression[callee.object.object.name=Scratch][callee.object.property.name=translate][callee.property.name=setup]',
+          message: 'Do not call Scratch.translate.setup() yourself. Just use Scratch.translate() and let the build script handle it.'
+        },
+        {
+          selector: 'MethodDefinition[key.name=getInfo] Property[key.name=id][value.callee.property.name=translate]',
+          message: 'Do not translate extension ID'
+        },
+        {
+          selector: 'MethodDefinition[key.name=docsURI] Property[key.name=id][value.callee.property.name=translate]',
+          message: 'Do not translate docsURI'
+        },
+        {
+          selector: 'MethodDefinition[key.name=getInfo] Property[key.name=opcode][value.callee.property.name=translate]',
+          message: 'Do not translate block opcode'
+        },
+        {
+          selector: 'MemberExpression[object.name=window][property.name=vm]',
+          message: 'Use Scratch.vm instead of window.vm'
+        }
+      ]
+    }
+  }
+];