Add eslint-plugin package

packages/eslint-plugin/.eslintrc.js

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+"use strict";
+
+module.exports = {
+  root: true,
+  parserOptions: {
+    ecmaVersion: 'latest'
+  },
+  extends: [
+    "eslint:recommended",
+    "plugin:eslint-plugin/recommended",
+    "plugin:node/recommended",
+  ],
+  env: {
+    node: true,
+  },
+  overrides: [
+    {
+      files: ["tests/**/*.js"],
+      env: { mocha: true },
+    },
+  ]
+};

packages/eslint-plugin/.gitignore

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+/node_modules
+dist

packages/eslint-plugin/README.md

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+# eslint-plugin-opticks
+
+Opticks
+
+## Installation
+
+You'll first need to install [ESLint](https://eslint.org/):
+
+```sh
+npm i eslint --save-dev
+```
+
+Next, install `eslint-plugin-opticks`:
+
+```sh
+npm install eslint-plugin-opticks --save-dev
+```
+
+## Usage
+
+Add `opticks` to the plugins section of your `.eslintrc` configuration file. You can omit the `eslint-plugin-` prefix:
+
+```json
+{
+    "plugins": [
+        "opticks"
+    ]
+}
+```
+
+
+Then configure the rules you want to use under the rules section.
+
+```json
+{
+    "rules": {
+        "opticks/rule-name": 2
+    }
+}
+```
+
+## Rules
+
+<!-- begin auto-generated rules list -->
+TODO: Run eslint-doc-generator to generate the rules list.
+<!-- end auto-generated rules list -->
+
+

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

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+# Opticks (`opticks`)
+
+Please describe the origin of the rule here.
+
+## Rule Details
+
+This rule aims to...
+
+Examples of **incorrect** code for this rule:
+
+```js
+
+// fill me in
+
+```
+
+Examples of **correct** code for this rule:
+
+```js
+
+// fill me in
+
+```
+
+### Options
+
+If there are any options, describe them here. Otherwise, delete this section.
+
+## When Not To Use It
+
+Give a short description of when it would be appropriate to turn off this rule.
+
+## Further Reading
+
+If there are other links that describe the issue this rule addresses, please include them here in a bulleted list.

packages/eslint-plugin/lib/index.js

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+/**
+ * @fileoverview Opticks
+ * @author Jop
+ */
+"use strict";
+
+//------------------------------------------------------------------------------
+// Requirements
+//------------------------------------------------------------------------------
+
+const requireIndex = require("requireindex");
+
+//------------------------------------------------------------------------------
+// Plugin Definition
+//------------------------------------------------------------------------------
+
+
+// import all rules in lib/rules
+module.exports.rules = requireIndex(__dirname + "/rules");
+
+
+

packages/eslint-plugin/lib/rules/toggle.js

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+/**
+ * @fileoverview Opticks
+ * @author Jop
+ */
+"use strict";
+
+//------------------------------------------------------------------------------
+// Rule Definition
+//------------------------------------------------------------------------------
+
+/** @type {import('eslint').Rule.RuleModule} */
+module.exports = {
+  meta: {
+    type: "problem",
+    docs: {
+      description: "Detects stale code from expired Opticks experiments",
+      recommended: false,
+      url: null, // URL to the documentation page for this rule
+    },
+    fixable: "code",
+    hasSuggestions: true,
+    schema: [], // Add a schema if the rule has options
+    messages: {
+      ExperimentNotConfigured:
+        "Looks like this experiment is not configured. Please make sure the experiment is added to the experiments config file.",
+      ExperimentConcluded:
+        "Looks like this experiment concluded, and can be cleaned up. The winning variant is {{winningVariant}}.",
+      AddWinningVariant:
+        "If the experiment is concluded, add the winning variant.",
+      VariableAssignment:
+        "It is okay to assign the result of a toggle to a variable, but you might be better off calling the toggle inline for automatic clean up.",
+      InvalidNrOfVariants:
+        "Invalid number of variants. Toggles require either 0, 2, or more variants.",
+      AddNullBVariant:
+        "If the b side is not supposed to do anything, add a null value.",
+    },
+  },
+
+  create(context) {
+    // QUESTION it seems the test runner reads from `context.settings`
+    // while .eslintrc.js reads from `settings`
+    const settings = context.settings || settings;
+    const { opticks } = settings;
+    // variables should be defined here
+
+    //----------------------------------------------------------------------
+    // Helpers
+    //----------------------------------------------------------------------
+
+    // any helper functions should go here or else delete this section
+
+    //----------------------------------------------------------------------
+    // Public
+    //----------------------------------------------------------------------
+
+    return {
+      CallExpression: (node) => {
+        const {
+          callee: { name },
+        } = node;
+        // TODO: look for imported toggles from opticks only
+        if (name === "toggle") {
+          if (node.arguments.length === 2) {
+            return context.report({
+              messageId: "InvalidNrOfVariants",
+              node,
+              suggest: [
+                {
+                  messageId: "AddNullBVariant",
+                  fix: (fixer) => {
+                    const { range } = node;
+                    // TODO: How to work with multilines
+                    return fixer.insertTextBeforeRange(
+                      [range[1] - 1],
+                      ", null"
+                    );
+                  },
+                },
+              ],
+            });
+          }
+          // Clean up
+          const winningVariant = opticks.experiments[node.arguments[0].value];
+
+          if (typeof winningVariant === 'undefined') {
+            return context.report({
+              messageId: "ExperimentNotConfigured",
+              node
+            });
+          }
+
+          // TODO: Support unlimited amount of arguments
+          // TODO: Support arrow function replacement
+          const winningVariantIndex = winningVariant === "a" ? 1 : 2;
+          const winningVariantContent = node.arguments[winningVariantIndex].raw;
+
+          if (typeof winningVariant === "string") {
+            return context.report({
+              messageId: "ExperimentConcluded",
+              data: { winningVariant },
+              node,
+              suggests: [
+                {
+                  messageId: "AddWinningVariant",
+                  fix: (fixer) => {
+                    // TODO: Add tests
+                    console.log(winningVariantContent);
+                    return fixer.replaceText(node, winningVariantContent);
+                  },
+                }
+              ],
+            });
+          }
+
+          // Discourage variable assignment
+          if (node.parent.type === "VariableDeclarator") {
+            return context.report({
+              messageId: "VariableAssignment",
+              node,
+            });
+          }
+        }
+      },
+      // visitor functions for different types of nodes
+    };
+  },
+};

packages/eslint-plugin/package.json

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+{
+  "name": "eslint-plugin-opticks",
+  "version": "0.0.1",
+  "description": "Opticks",
+  "keywords": [
+    "eslint",
+    "eslintplugin",
+    "eslint-plugin"
+  ],
+  "author": "Jop de Klein",
+  "main": "./lib/index.js",
+  "exports": "./lib/index.js",
+  "scripts": {
+    "lint": "npm-run-all \"lint:*\"",
+    "lint:eslint-docs": "npm-run-all \"update:eslint-docs -- --check\"",
+    "lint:js": "eslint .",
+    "test": "mocha tests --recursive",
+    "update:eslint-docs": "eslint-doc-generator"
+  },
+  "dependencies": {
+    "requireindex": "^1.2.0"
+  },
+  "devDependencies": {
+    "eslint": "^8.19.0",
+    "eslint-doc-generator": "^1.0.0",
+    "eslint-plugin-eslint-plugin": "^5.0.0",
+    "eslint-plugin-node": "^11.1.0",
+    "mocha": "^10.0.0",
+    "npm-run-all": "^4.1.5"
+  },
+  "engines": {
+    "node": "^14.17.0 || ^16.0.0 || >= 18.0.0"
+  },
+  "peerDependencies": {
+    "eslint": ">=7"
+  },
+  "license": "ISC"
+}

packages/eslint-plugin/tests/lib/rules/toggle.js

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+/**
+ * @fileoverview Opticks
+ * @author Jop
+ */
+"use strict";
+
+//------------------------------------------------------------------------------
+// Requirements
+//------------------------------------------------------------------------------
+
+const rule = require("../../../lib/rules/toggle"),
+  RuleTester = require("eslint").RuleTester;
+
+//------------------------------------------------------------------------------
+// Tests
+//------------------------------------------------------------------------------
+
+RuleTester.setDefaultConfig({
+  settings: {
+    opticks: { experiments: { foo: "a", bar: undefined, baz: "b" } },
+  },
+});
+const ruleTester = new RuleTester();
+
+ruleTester.run("toggle", rule, {
+  valid: [
+    { code: "toggle('bar', 'a', 'b')" },
+    { code: "toggle('nonexistent', 'a', 'b')" },
+  ],
+  invalid: [
+    {
+      code: "toggle('foo', 'a', 'b')",
+      errors: [
+        {
+          message:
+            "Looks like this experiment concluded, and can be cleaned. The winning variant is a.",
+          type: "CallExpression",
+        },
+      ],
+      output: "'a'",
+    },
+    {
+      code: "toggle('baz', 'a', 'b')",
+      errors: [
+        {
+          messageId: "ExperimentConcluded",
+          type: "CallExpression",
+        },
+      ],
+      output: "'b'",
+    },
+    {
+      // TODO: make tests work with const too
+      code: "var intermediateVariable = toggle('bar', 'a', 'b')",
+      errors: [
+        {
+          messageId: "VariableAssignment",
+          type: "CallExpression",
+        },
+      ],
+      output: null,
+    },
+    {
+      code: "toggle('bar', 'a')",
+      errors: [
+        {
+          messageId: "InvalidNrOfVariants",
+          type: "CallExpression",
+          suggestions: [
+            {
+              messageId: "AddNullBVariant",
+              output: "toggle('bar', 'a', null)",
+            },
+          ],
+        },
+      ],
+      output: null,
+    },
+    {
+      code: `var Foo = styled('div')\`
+          display: flex;
+          \${toggle("foo", "a", "b")}
+        \`
+      `,
+      errors: [
+        "This toggle is not called from a function, this might not be what you want to do because it might execute before Opticks received the user id. Is this intended?",
+      ],
+      output: null,
+    },
+  ],
+});