remove flow and all flow checks

Author: sndrs

.flowconfig

@@ -1,7 +1,6 @@
 module.exports = {
     "presets": [
-        "@babel/preset-react",
-        "@babel/preset-flow"
+        "@babel/preset-react"
     ],
     "plugins": [
         "@babel/plugin-proposal-object-rest-spread",

babel.config.js

@@ -66,7 +66,6 @@
     "@babel/plugin-syntax-dynamic-import": "^7.8.3",
     "@babel/plugin-transform-runtime": "^7.11.5",
     "@babel/preset-env": "^7.11.5",
-    "@babel/preset-flow": "^7.10.4",
     "@babel/preset-react": "^7.10.4",
     "@babel/register": "^7.11.5",
     "amphtml-validator": "^1.0.21",
@@ -92,8 +91,6 @@
     "eslint-config-airbnb": "^16.1.0",
     "eslint-config-prettier": "^2.9.0",
     "eslint-import-resolver-webpack": "^0.10.0",
-    "eslint-plugin-flow-header": "^0.2.0",
-    "eslint-plugin-flowtype": "^2.49.0",
     "eslint-plugin-guardian-frontend": "file:tools/eslint-plugin-guardian-frontend",
     "eslint-plugin-import": "^2.12.0",
     "eslint-plugin-jasmine": "^2.10.1",
@@ -102,8 +99,6 @@
     "eslint-plugin-react": "^7.8.2",
     "execa": "^0.8.0",
     "figures": "^2.0.0",
-    "flow-bin": "^0.89.0",
-    "flow-typed": "^2.5.1",
     "glob": "^7.1.2",
     "gzip-size": "^3.0.0",
     "hasha": "^3.0.0",
@@ -182,7 +177,6 @@
   "scripts": {
     "postinstall": "./tools/sync-githooks.js",
     "eslint-fix": "eslint --color --fix",
-    "flow": "flow",
     "test": "jest"
   },
   "prettier": {
@@ -191,6 +185,6 @@
     "bracketSpacing": true,
     "tabWidth": 4,
     "jsxBracketSameLine": true,
-    "parser": "flow"
+    "parser": "babel"
   }
 }

package.json

@@ -1,4 +1,3 @@
-// @flow
 module.exports = {
     env: {
         browser: true,
@@ -13,11 +12,8 @@ module.exports = {
         'import/resolver': 'webpack',
     },
     extends: [
-        'plugin:flowtype/recommended',
-        'prettier/flowtype',
         'prettier/react',
     ],
-    plugins: ['flowtype', 'flow-header'],
     rules: {
         // require-specific overrides
         'import/extensions': 'off',
@@ -70,7 +66,6 @@ module.exports = {
             },
         ],
 
-        'flow-header/flow-header': 'error',
         'no-param-reassign': ['error', { props: false }],
         'no-prototype-builtins': 'off',
 
@@ -81,7 +76,7 @@ module.exports = {
         'guardian-frontend/no-default-export': 'warn',
         'guardian-frontend/no-direct-access-config': 'warn',
 
-        // flow should take care of our return values
+        // flow (used to) take care of our return values (although, did it really?)
         'consistent-return': 'off',
     },
 };

static/src/javascripts/.eslintrc.js

@@ -76,22 +76,6 @@ module.exports = {
                         });
                 }),
         },
-        {
-            description: 'Run Flowtype checks',
-            task: () =>
-                getChangedFiles().then(files => {
-                    const jsFiles = files.filter(
-                        file =>
-                            file.endsWith('.js') && file.startsWith('static')
-                    );
-
-                    if (jsFiles.length) {
-                        return execa('yarn', ['flow']);
-                    }
-
-                    return Promise.resolve();
-                }),
-        },
     ],
     concurrent: true,
 };

tools/__tasks__/validate-head/javascript.js

@@ -1,7 +1,6 @@
 const fs = require('fs');
 
 const chalk = require('chalk');
-const execa = require('execa');
 
 const config = '--quiet --color';
 
@@ -16,21 +15,14 @@ const error = ctx => {
     );
 };
 
-const flowError = ctx => {
-    ctx.messages.push(
-        `Your editor may be able to catch flow errors as you work:\n${chalk.underline(
-            'https://flow.org/en/docs/editors'
-        )}`
-    );
-};
+
 const dirs = p =>
     fs.readdirSync(p).filter(f => fs.statSync(`${p}/${f}`).isDirectory());
 
 module.exports = {
     description: 'Lint JS',
     task: [
         ...dirs('static/src/javascripts')
-            .filter(dir => !['__flow__'].includes(dir))
             .map(dir => ({
                 description: `App ${chalk.dim(dir)}`,
                 task: `eslint static/src/javascripts/${dir} ${config}`,
@@ -41,11 +33,6 @@ module.exports = {
             task: `eslint --ignore-pattern /static/src --ignore-pattern . ${config}`,
             onError: error,
         },
-        {
-            description: 'Flow',
-            task: () => execa('flow'),
-            onError: flowError,
-        },
         {
             description: 'Git hooks',
             task: `eslint git-hooks/* ${config}`,