Enable eslint:recommended ruleset (#22433)

* Enable ESLint recommended ruleset

* Disable failing ESLint recommended rules

* Remove rules shadowed by eslint:recommended

74 files changed, 350 insertions, 348 deletions

diff --git a/.eslintrc.js b/.eslintrc.js
index e4ada6fe0d1..03af2975b83 100644
--- a/.eslintrc.js
+++ b/.eslintrc.js
@@ -1,6 +1,10 @@
 module.exports = {
   root: true,
 
+  extends: [
+    'eslint:recommended',
+  ],
+
   env: {
     browser: true,
     node: true,
@@ -64,8 +68,8 @@ module.exports = {
     eqeqeq: 'error',
     indent: ['warn', 2],
     'jsx-quotes': ['error', 'prefer-single'],
+    'no-case-declarations': 'off',
     'no-catch-shadow': 'error',
-    'no-cond-assign': 'error',
     'no-console': [
       'warn',
       {
@@ -75,18 +79,16 @@ module.exports = {
         ],
       },
     ],
-    'no-fallthrough': 'error',
-    'no-irregular-whitespace': 'error',
-    'no-mixed-spaces-and-tabs': 'warn',
+    'no-empty': 'off',
     'no-nested-ternary': 'warn',
+    'no-prototype-builtins': 'off',
     'no-restricted-properties': [
       'error',
       { property: 'substring', message: 'Use .slice instead of .substring.' },
       { property: 'substr', message: 'Use .slice instead of .substr.' },
     ],
+    'no-self-assign': 'off',
     'no-trailing-spaces': 'warn',
-    'no-undef': 'error',
-    'no-unreachable': 'error',
     'no-unused-expressions': 'error',
     'no-unused-vars': [
       'error',
@@ -96,6 +98,7 @@ module.exports = {
         ignoreRestSiblings: true,
       },
     ],
+    'no-useless-escape': 'off',
     'object-curly-spacing': ['error', 'always'],
     'padded-blocks': [
       'error',
@@ -105,7 +108,6 @@ module.exports = {
     ],
     quotes: ['error', 'single'],
     semi: 'error',
-    strict: 'off',
     'valid-typeof': 'error',
 
     'react/jsx-boolean-value': 'error',
diff --git a/app/javascript/mastodon/actions/account_notes.js b/app/javascript/mastodon/actions/account_notes.js
index d1744100025..72b943300d8 100644
--- a/app/javascript/mastodon/actions/account_notes.js
+++ b/app/javascript/mastodon/actions/account_notes.js
@@ -14,24 +14,24 @@ export function submitAccountNote(id, value) {
       dispatch(submitAccountNoteSuccess(response.data));
     }).catch(error => dispatch(submitAccountNoteFail(error)));
   };
-};
+}
 
 export function submitAccountNoteRequest() {
   return {
     type: ACCOUNT_NOTE_SUBMIT_REQUEST,
   };
-};
+}
 
 export function submitAccountNoteSuccess(relationship) {
   return {
     type: ACCOUNT_NOTE_SUBMIT_SUCCESS,
     relationship,
   };
-};
+}
 
 export function submitAccountNoteFail(error) {
   return {
     type: ACCOUNT_NOTE_SUBMIT_FAIL,
     error,
   };
-};
+}
diff --git a/app/javascript/mastodon/actions/accounts.js b/app/javascript/mastodon/actions/accounts.js
index f61f06e408f..88407ae6cf3 100644
--- a/app/javascript/mastodon/actions/accounts.js
+++ b/app/javascript/mastodon/actions/accounts.js
@@ -91,7 +91,7 @@ export function fetchAccount(id) {
       dispatch(fetchAccountFail(id, error));
     });
   };
-};
+}
 
 export const lookupAccount = acct => (dispatch, getState) => {
   dispatch(lookupAccountRequest(acct));
@@ -126,13 +126,13 @@ export function fetchAccountRequest(id) {
     type: ACCOUNT_FETCH_REQUEST,
     id,
   };
-};
+}
 
 export function fetchAccountSuccess() {
   return {
     type: ACCOUNT_FETCH_SUCCESS,
   };
-};
+}
 
 export function fetchAccountFail(id, error) {
   return {
@@ -141,7 +141,7 @@ export function fetchAccountFail(id, error) {
     error,
     skipAlert: true,
   };
-};
+}
 
 export function followAccount(id, options = { reblogs: true }) {
   return (dispatch, getState) => {
@@ -156,7 +156,7 @@ export function followAccount(id, options = { reblogs: true }) {
       dispatch(followAccountFail(error, locked));
     });
   };
-};
+}
 
 export function unfollowAccount(id) {
   return (dispatch, getState) => {
@@ -168,7 +168,7 @@ export function unfollowAccount(id) {
       dispatch(unfollowAccountFail(error));
     });
   };
-};
+}
 
 export function followAccountRequest(id, locked) {
   return {
@@ -177,7 +177,7 @@ export function followAccountRequest(id, locked) {
     locked,
     skipLoading: true,
   };
-};
+}
 
 export function followAccountSuccess(relationship, alreadyFollowing) {
   return {
@@ -186,7 +186,7 @@ export function followAccountSuccess(relationship, alreadyFollowing) {
     alreadyFollowing,
     skipLoading: true,
   };
-};
+}
 
 export function followAccountFail(error, locked) {
   return {
@@ -195,7 +195,7 @@ export function followAccountFail(error, locked) {
     locked,
     skipLoading: true,
   };
-};
+}
 
 export function unfollowAccountRequest(id) {
   return {
@@ -203,7 +203,7 @@ export function unfollowAccountRequest(id) {
     id,
     skipLoading: true,
   };
-};
+}
 
 export function unfollowAccountSuccess(relationship, statuses) {
   return {
@@ -212,7 +212,7 @@ export function unfollowAccountSuccess(relationship, statuses) {
     statuses,
     skipLoading: true,
   };
-};
+}
 
 export function unfollowAccountFail(error) {
   return {
@@ -220,7 +220,7 @@ export function unfollowAccountFail(error) {
     error,
     skipLoading: true,
   };
-};
+}
 
 export function blockAccount(id) {
   return (dispatch, getState) => {
@@ -233,7 +233,7 @@ export function blockAccount(id) {
       dispatch(blockAccountFail(id, error));
     });
   };
-};
+}
 
 export function unblockAccount(id) {
   return (dispatch, getState) => {
@@ -245,14 +245,14 @@ export function unblockAccount(id) {
       dispatch(unblockAccountFail(id, error));
     });
   };
-};
+}
 
 export function blockAccountRequest(id) {
   return {
     type: ACCOUNT_BLOCK_REQUEST,
     id,
   };
-};
+}
 
 export function blockAccountSuccess(relationship, statuses) {
   return {
@@ -260,35 +260,35 @@ export function blockAccountSuccess(relationship, statuses) {
     relationship,
     statuses,
   };
-};
+}
 
 export function blockAccountFail(error) {
   return {
     type: ACCOUNT_BLOCK_FAIL,
     error,
   };
-};
+}
 
 export function unblockAccountRequest(id) {
   return {
     type: ACCOUNT_UNBLOCK_REQUEST,
     id,
   };
-};
+}
 
 export function unblockAccountSuccess(relationship) {
   return {
     type: ACCOUNT_UNBLOCK_SUCCESS,
     relationship,
   };
-};
+}
 
 export function unblockAccountFail(error) {
   return {
     type: ACCOUNT_UNBLOCK_FAIL,
     error,
   };
-};
+}
 
 
 export function muteAccount(id, notifications, duration=0) {
@@ -302,7 +302,7 @@ export function muteAccount(id, notifications, duration=0) {
       dispatch(muteAccountFail(id, error));
     });
   };
-};
+}
 
 export function unmuteAccount(id) {
   return (dispatch,