diff --git a/.eslintrc.js b/.eslintrc.js
index 5ed8d71a..680376ea 100644
--- a/.eslintrc.js
+++ b/.eslintrc.js
@@ -15,6 +15,7 @@ module.exports = {
   },
   rules: {
     'import/no-named-as-default': 0,
+    'unicorn/consistent-function-scoping': 0,
     'vue/attributes-order': 0,
     'vue/no-v-html': 0,
     'no-confusing-arrow': 0,
@@ -24,9 +25,11 @@ module.exports = {
     'prefer-destructuring': 0,
   },
   overrides: [ {
-    files: [ 'docs/**', 'test/**' ],
+    files: [ 'src/**' ],
     rules: {
-      'require-atomic-updates': 0,
+      'unicorn/no-for-loop': 0,
+      'unicorn/prefer-includes': 0,
+      'unicorn/prefer-node-append': 0,
     },
   } ],
 }
diff --git a/build/dev-client.js b/build/dev-client.js
index 18aa1e21..b7ad7e93 100644
--- a/build/dev-client.js
+++ b/build/dev-client.js
@@ -1,3 +1,4 @@
+/* eslint-disable unicorn/no-abusive-eslint-disable */
 /* eslint-disable */
 require('eventsource-polyfill')
 var hotClient = require('webpack-hot-middleware/client?noInfo=true&reload=true')
diff --git a/build/webpack.bundle.prod.conf.js b/build/webpack.bundle.prod.conf.js
index 6227c828..a6eb8323 100644
--- a/build/webpack.bundle.prod.conf.js
+++ b/build/webpack.bundle.prod.conf.js
@@ -44,8 +44,8 @@ const webpackConfig = merge(base, {
   optimization: {
     minimizer: [
       new TerserPlugin({
-        parallel: true,
         sourceMap: config.bundle.prod.productionSourceMap,
+        extractComments: false,
       }),
       new OptimizeJsPlugin({
         sourceMap: config.bundle.prod.productionSourceMap,
diff --git a/build/webpack.docs.conf.js b/build/webpack.docs.conf.js
index 249263a3..c8af1fbf 100644
--- a/build/webpack.docs.conf.js
+++ b/build/webpack.docs.conf.js
@@ -75,8 +75,8 @@ const webpackConfig = merge(baseWebpackConfig, {
   optimization: {
     minimizer: [
       new TerserPlugin({
-        parallel: true,
         sourceMap: config.docs.productionSourceMap,
+        extractComments: false,
       }),
       new OptimizeJsPlugin({ sourceMap: config.docs.productionSourceMap }),
       new OptimizeCSSPlugin(),
diff --git a/package.json b/package.json
index b04a6154..f1409ef3 100755
--- a/package.json
+++ b/package.json
@@ -61,19 +61,20 @@
     "css-loader": "^3.0.0",
     "entities": "^2.0.0",
     "eslint": "^6.1.0",
-    "eslint-config-riophae": "^0.8.0",
+    "eslint-config-riophae": "^0.9.1",
     "eslint-friendly-formatter": "^4.0.0",
     "eslint-import-resolver-webpack": "^0.11.0",
-    "eslint-loader": "^2.1.0",
+    "eslint-loader": "^3.0.0",
     "eslint-plugin-import": "^2.15.0",
     "eslint-plugin-react": "^7.10.0",
+    "eslint-plugin-unicorn": "^11.0.2",
     "eslint-plugin-vue": "^5.1.0",
     "eventsource-polyfill": "^0.9.6",
     "express": "^4.16.3",
     "friendly-errors-webpack-plugin": "^1.7.0",
     "gh-pages": "^2.0.0",
     "html-webpack-plugin": "^3.1.0",
-    "http-proxy-middleware": "^0.19.0",
+    "http-proxy-middleware": "^0.20.0",
     "jasmine-core": "^3.1.0",
     "jstransformer-markdown-it": "^2.0.0",
     "karma": "^4.0.0",
@@ -90,7 +91,7 @@
     "open": "^6.2.0",
     "optimize-css-assets-webpack-plugin": "^5.0.0",
     "optimize-js-plugin": "0.0.4",
-    "ora": "^3.0.0",
+    "ora": "^4.0.1",
     "postcss-loader": "^3.0.0",
     "pre-commit": "^1.2.2",
     "pug": "^2.0.0",
@@ -105,9 +106,9 @@
     "size-limit": "^2.0.2",
     "string.prototype.repeat": "^0.2.0",
     "strip-indent": "^3.0.0",
-    "stylelint": "^10.0.1",
+    "stylelint": "^11.0.0",
     "stylelint-config-xo-space": "^0.13.0",
-    "terser-webpack-plugin": "^1.2.1",
+    "terser-webpack-plugin": "^2.1.0",
     "url-loader": "^2.0.1",
     "vodal": "^2.3.3",
     "vue": "^2.2.0",
diff --git a/src/mixins/treeselectMixin.js b/src/mixins/treeselectMixin.js
index 2365fe60..c9de00b5 100644
--- a/src/mixins/treeselectMixin.js
+++ b/src/mixins/treeselectMixin.js
@@ -1305,10 +1305,14 @@ export default {
       }
 
       // Vue doesn't support directly watching on objects.
-      this.$watch(() => entry.options, () => {
-        // TODO: potential redundant re-initialization.
-        if (this.trigger.searchQuery === searchQuery) this.initialize()
-      }, { deep: true })
+      this.$watch(
+        () => entry.options,
+        () => {
+          // TODO: potential redundant re-initialization.
+          if (this.trigger.searchQuery === searchQuery) this.initialize()
+        },
+        { deep: true },
+      )
 
       if (searchQuery === '') {
         if (Array.isArray(this.defaultOptions)) {
diff --git a/stylelint.config.js b/stylelint.config.js
index 5a11f6d2..4c5ac940 100644
--- a/stylelint.config.js
+++ b/stylelint.config.js
@@ -14,7 +14,7 @@ module.exports = {
     'font-weight-notation': null,
     'no-descending-specificity': null,
     'selector-max-compound-selectors': null,
-    // Disable this rule temporarily as it causes stylelint to crash.
+    // Stylelint v11 is buggy with this rule.
     'block-no-empty': null,
   },
 }
diff --git a/test/unit/specs/utils.spec.js b/test/unit/specs/utils.spec.js
index 8bd220ed..869ac57f 100644
--- a/test/unit/specs/utils.spec.js
+++ b/test/unit/specs/utils.spec.js
@@ -98,7 +98,7 @@ describe('Utils', () => {
         $el = document.createElement('div')
         $el.style.height = (height = 100) + 'px'
         $el.style.position = 'relative'
-        document.body.appendChild($el)
+        document.body.append($el)
         log = []
       }
       const cleanup = () => {
@@ -142,12 +142,14 @@ describe('Utils', () => {
 
       const init = () => {
         grandparent = document.createElement('div')
+        // eslint-disable-next-line unicorn/prefer-node-append
         parent = grandparent.appendChild(document.createElement('div'))
         parent.style.overflow = 'auto'
         parent.style.height = '100px'
+        // eslint-disable-next-line unicorn/prefer-node-append
         child = parent.appendChild(document.createElement('div'))
         child.style.height = '99999px'
-        document.body.appendChild(grandparent)
+        document.body.append(grandparent)
         called = 0
       }
       const cleanup = () => {