feat: add eslint-graph-config package

Signed-off-by: Tomás Migone <[email protected]>

README.md

@@ -37,6 +37,8 @@ This repository is a Yarn workspaces monorepo containing the following packages:
 | Package | Latest version | Description |
 | --- | --- | --- |
 | [contracts](./packages/contracts) | [![npm version](https://badge.fury.io/js/@graphprotocol%2Fcontracts.svg)](https://badge.fury.io/js/@graphprotocol%2Fcontracts) | Contracts enabling the open and permissionless decentralized network known as The Graph protocol. |
+| [eslint-graph-config](./packages/eslint-graph-config) | [![npm version]()]() | Shared linting and formatting rules for TypeScript projects. |
+| [subgraph-service](./packages/subgraph-service) | [![npm version]()]() | Contracts for the Subgraph data service in Graph Horizon. |
 | [sdk](./packages/sdk) | [![npm version](https://badge.fury.io/js/@graphprotocol%2Fsdk.svg)](https://badge.fury.io/js/@graphprotocol%2Fsdk) | TypeScript based SDK to interact with the protocol contracts |
 
 

package.json

@@ -8,6 +8,7 @@
   "packageManager": "[email protected]",
   "workspaces": [
     "packages/contracts",
+    "packages/eslint-graph-config",
     "packages/subgraph-service",
     "packages/sdk"
   ],

packages/eslint-graph-config/README.md

@@ -0,0 +1,48 @@
+# eslint-graph-config
+
+This repository contains shared linting and formatting rules for TypeScript projects.
+
+## Installation
+
+```bash
+yarn add --dev eslint eslint-graph-config
+```
+
+For projects on this monorepo, you can use the following command to install the package:
+
+```bash
+yarn add --dev eslint eslint-graph-config@workspace:^x.y.z
+```
+
+To enable the rules, you need to create an `eslint.config.js` file in the root of your project with the following content:
+
+```javascript
+import eslintGraphConfig from 'eslint-graph-config'
+export default eslintGraphConfig
+```
+
+## Tooling
+
+This package uses the following tools:
+- [ESLint](https://eslint.org/) as the base linting tool
+- [typescript-eslint](https://typescript-eslint.io/) for TypeScript support
+- [ESLint Stylistic](https://eslint.style/) as the formatting tool
+
+**Why no prettier?**
+Instead of prettier we use ESLint Stylistic which is a set of ESLint rules focused on formatting and styling code. As opposed to prettier, ESLint Stylistic runs entirely within ESLint and does not require a separate tool to be run (e.g. `prettier`, `eslint-plugin-prettier` and `eslint-config-prettier`). Additionally it's supposed to be [more efficient](https://eslint.style/guide/why#linters-vs-formatters) and [less opinionated](https://antfu.me/posts/why-not-prettier).
+
+## VSCode support
+
+If you are using VSCode you can install the [ESLint extension](https://marketplace.visualstudio.com/items?itemName=dbaeumer.vscode-eslint) to get real-time linting and formatting support.
+
+The following settings should be added to your `settings.json` file:
+```json
+{
+  "editor.defaultFormatter": "dbaeumer.vscode-eslint",
+  "eslint.format.enable": true,
+  "eslint.experimental.useFlatConfig": true,
+  "eslint.workingDirectories": [{ "pattern": "./packages/*/" }]
+}
+```
+
+Additionally you can configure the `Format document` keyboard shortcut to run `eslint --fix` on demand.

packages/eslint-graph-config/eslint.config.js

@@ -0,0 +1,3 @@
+// This file only exists to enable linting on index.js
+import config from './index.js'
+export default config

packages/eslint-graph-config/index.js

@@ -0,0 +1,53 @@
+// @ts-check
+
+/* eslint-disable @typescript-eslint/no-unsafe-assignment */
+/* eslint-disable @typescript-eslint/no-unsafe-member-access */
+/* eslint-disable @typescript-eslint/no-unsafe-argument */
+
+import eslint from '@eslint/js'
+import noOnlyTests from 'eslint-plugin-no-only-tests'
+import noSecrets from 'eslint-plugin-no-secrets'
+import stylistic from '@stylistic/eslint-plugin'
+import tseslint from 'typescript-eslint'
+
+export default tseslint.config(
+  // Base eslint configuration
+  // @ts-expect-error tseslint doesn't recognize eslint types for some reason
+  eslint.configs.recommended,
+
+  // Enable linting with type information
+  // https://typescript-eslint.io/getting-started/typed-linting
+  ...tseslint.configs.recommendedTypeChecked,
+  {
+    languageOptions: {
+      parserOptions: {
+        project: true,
+        tsconfigRootDir: import.meta.dirname,
+      },
+    },
+  },
+
+  // Formatting and stylistic rules
+  stylistic.configs['recommended-flat'],
+
+  // Custom rules
+  {
+    plugins: {
+      'no-only-tests': noOnlyTests,
+      'no-secrets': noSecrets,
+    },
+    rules: {
+      'prefer-const': 'warn',
+      '@typescript-eslint/no-inferrable-types': 'warn',
+      '@typescript-eslint/no-empty-function': 'warn',
+      'no-only-tests/no-only-tests': 'error',
+      'no-secrets/no-secrets': 'error',
+      'sort-imports': [
+        'warn', {
+          memberSyntaxSortOrder: ['none', 'all', 'multiple', 'single'],
+          ignoreCase: true,
+          allowSeparatedGroups: true,
+        }],
+    },
+  },
+)

packages/eslint-graph-config/package.json

@@ -0,0 +1,17 @@
+{
+  "name": "eslint-graph-config",
+  "version": "0.0.1",
+  "description": "Linting and formatting rules for The Graph's TypeScript projects",
+  "main": "index.js",
+  "type": "module",
+  "author": "The Graph Team",
+  "license": "GPL-2.0-or-later",
+  "devDependencies": {
+    "@stylistic/eslint-plugin": "^1.6.2",
+    "eslint": "^8.56.0",
+    "eslint-plugin-no-only-tests": "^3.1.0",
+    "eslint-plugin-no-secrets": "^0.8.9",
+    "typescript": "^5.3.3",
+    "typescript-eslint": "^7.0.2"
+  }
+}

packages/eslint-graph-config/tsconfig.json

@@ -0,0 +1,11 @@
+{
+  "compilerOptions": {
+    "target": "es2020",
+    "module": "commonjs",
+    "esModuleInterop": true,
+    "forceConsistentCasingInFileNames": true,
+    "strict": true,
+    "skipLibCheck": true,
+    "resolveJsonModule": true
+  }
+}