router

package.json

   "dependencies": {
     "core-js": "^3.8.3",
     "two.js": "^0.8.4",
-    "vue": "^3.2.13"
+    "vue": "^3.2.13",
+    "vue-router": "4"
   },
   "devDependencies": {
     "@babel/core": "^7.12.16",

yarn.lock

   optionalDependencies:
     prettier "^1.18.2 || ^2.0.0"
 
+"@vue/devtools-api@^6.0.0":
+  version "6.1.4"
+  resolved "https://registry.yarnpkg.com/@vue/devtools-api/-/devtools-api-6.1.4.tgz#b4aec2f4b4599e11ba774a50c67fa378c9824e53"
+  integrity sha512-IiA0SvDrJEgXvVxjNkHPFfDx6SXw0b/TUkqMcDZWNg9fnCAHbTpoo59YfJ9QLFkwa3raau5vSlRVzMSLDnfdtQ==
+
 "@vue/reactivity-transform@3.2.31":
   version "3.2.31"
   resolved "https://registry.yarnpkg.com/@vue/reactivity-transform/-/reactivity-transform-3.2.31.tgz#0f5b25c24e70edab2b613d5305c465b50fc00911"
     hash-sum "^2.0.0"
     loader-utils "^2.0.0"
 
+vue-router@4:
+  version "4.0.14"
+  resolved "https://registry.yarnpkg.com/vue-router/-/vue-router-4.0.14.tgz#ce2028c1c5c33e30c7287950c973f397fce1bd65"
+  integrity sha512-wAO6zF9zxA3u+7AkMPqw9LjoUCjSxfFvINQj3E/DceTt6uEz1XZLraDhdg2EYmvVwTBSGlLYsUw8bDmx0754Mw==
+  dependencies:
+    "@vue/devtools-api" "^6.0.0"
+
 vue-style-loader@^4.1.0, vue-style-loader@^4.1.3:
   version "4.1.3"
   resolved "https://registry.yarnpkg.com/vue-style-loader/-/vue-style-loader-4.1.3.tgz#6d55863a51fa757ab24e89d9371465072aa7bc35"