upgrade packages & fix lint errors

package.json

@@ -19,19 +19,19 @@
     "build": "npm-run-all clean build:webpack build:web-ext"
   },
   "devDependencies": {
-    "@babel/core": "^7.5.5",
-    "@babel/preset-env": "^7.5.5",
+    "@babel/core": "^7.8.0",
+    "@babel/preset-env": "^7.8.0",
     "babel-loader": "^8.0.6",
-    "copy-webpack-plugin": "^5.0.3",
-    "cross-env": "^5.2.0",
-    "eslint": "^5.16.0",
-    "eslint-config-airbnb-base": "^13.2.0",
-    "eslint-plugin-import": "^2.18.2",
+    "copy-webpack-plugin": "^5.1.1",
+    "cross-env": "^6.0.3",
+    "eslint": "^6.8.0",
+    "eslint-config-airbnb-base": "^14.0.0",
+    "eslint-plugin-import": "^2.20.0",
     "npm-run-all": "^4.1.5",
-    "rimraf": "^2.6.3",
-    "web-ext": "^3.1.1",
-    "webpack": "^4.36.1",
-    "webpack-cli": "^3.3.6",
+    "rimraf": "^3.0.0",
+    "web-ext": "^4.0.0",
+    "webpack": "^4.41.5",
+    "webpack-cli": "^3.3.10",
     "xregexp": "^4.2.4"
   }
 }

src/background/index.js

@@ -54,13 +54,12 @@ const openOptionsTab = () => openTab('options/options.html');
 
 const openPopupTab = () => openTab('popup/popup.html');
 
-window.openOptionsPage = () =>
-  browser.runtime.openOptionsPage()
-    .catch((err) => {
-      onError(err);
+window.openOptionsPage = () => browser.runtime.openOptionsPage()
+  .catch((err) => {
+    onError(err);
 
-      openOptionsTab();
-    });
+    openOptionsTab();
+  });
 
 
 // get storage
@@ -71,7 +70,7 @@ browser.storage.local.get()
     if (storage.preferences && Object.keys(storage.preferences).length === Object.keys(preferences).length) {
       ({ preferences } = storage);
     } else {
-      preferences = Object.assign({}, preferences, storage.preferences || {});
+      preferences = { ...preferences, ...storage.preferences || {} };
       newStorage.preferences = preferences;
     }
 
@@ -126,7 +125,7 @@ const checkCurrRate = (currRate, fromCurr, toCurr) => {
       showNotification(fromCurr, toCurr, oldValue, currRate.value);
     }
 
-    const newCurrRates = Object.assign({}, currRates, { [reqKey]: currRate });
+    const newCurrRates = { ...currRates, [reqKey]: currRate };
     browser.storage.local.set({ currRates: newCurrRates });
   }
 };

src/background/utils/getCurrRate.js

@@ -10,7 +10,7 @@ const getTxtMatch = (txt) => {
 
 // on getCurrRate request complete
 const reqComplete = (request, currRates, reqKey) => {
-  const currRate = currRates[reqKey] ? Object.assign({}, currRates[reqKey]) : {};
+  const currRate = currRates[reqKey] ? { ...currRates[reqKey] } : {};
 
   if (request && request.status === 200) {
     currRate.updatedAt = Date.now();

src/content/utils/mutationObserver.js

@@ -14,11 +14,10 @@ export default (onMutation) => {
   const observer = new MutationObserver(checkMutations);
 
   return {
-    observe: () =>
-      observer.observe(document.body, {
-        childList: true,
-        subtree: true,
-      }),
+    observe: () => observer.observe(document.body, {
+      childList: true,
+      subtree: true,
+    }),
 
     disconnect: () => observer.disconnect(),
   };

src/content/utils/style.js

@@ -1,18 +1,17 @@
 const styleElem = document.createElement('style');
-styleElem.textContent =
-  'data.scscc {\n' +
-  '  padding: 0 2px !important;\n' +
-  '  color: inherit !important;\n' +
-  '  white-space: pre !important;\n' +
-  '  border-width: 0 1px !important;\n' +
-  '  border-style: dotted !important;\n' +
-  '  border-color: inherit !important;\n' +
-  '  cursor: help !important;\n' +
-  '}\n' +
-  'data.scscc:hover {\n' +
-  '  background-color: red !important;\n' +
-  '  color: white !important;\n' +
-  '}';
+styleElem.textContent = 'data.scscc {\n'
+  + '  padding: 0 2px !important;\n'
+  + '  color: inherit !important;\n'
+  + '  white-space: pre !important;\n'
+  + '  border-width: 0 1px !important;\n'
+  + '  border-style: dotted !important;\n'
+  + '  border-color: inherit !important;\n'
+  + '  cursor: help !important;\n'
+  + '}\n'
+  + 'data.scscc:hover {\n'
+  + '  background-color: red !important;\n'
+  + '  color: white !important;\n'
+  + '}';
 
 export default {
   add: () => {

src/options/index.js

@@ -9,7 +9,7 @@ const onChange = ({ target }) => {
   if (Object.keys(changedPrefs).length) {
     browser.storage.local.get('preferences')
       .then((storage) => {
-        browser.storage.local.set({ preferences: Object.assign({}, storage.preferences, changedPrefs) });
+        browser.storage.local.set({ preferences: { ...storage.preferences, ...changedPrefs } });
       });
   }
 };