12 files changed, 173 insertions, 42 deletions

diff --git a/viewer/README.md b/viewer/README.md
index 2da36b3..864dcc6 100644
--- a/viewer/README.md
+++ b/viewer/README.md
@@ -1,5 +1,7 @@
 # ldgallery-viewer
 
+If you get errors with optionals and coalesce, enable the Vetur global preference: useWorkspaceDependencies
+
 ## Project setup
 ```
 npm install
diff --git a/viewer/babel.config.js b/viewer/babel.config.js
index 162a3ea..7102a6e 100644
--- a/viewer/babel.config.js
+++ b/viewer/babel.config.js
@@ -1,3 +1,7 @@
 module.exports = {
   presets: ["@vue/cli-plugin-babel/preset"],
+  plugins: [
+    '@babel/plugin-proposal-optional-chaining',
+    '@babel/plugin-proposal-nullish-coalescing-operator',
+  ],
 };
diff --git a/viewer/package-lock.json b/viewer/package-lock.json
index 8cf086a..10a0f26 100644
--- a/viewer/package-lock.json
+++ b/viewer/package-lock.json
@@ -343,6 +343,16 @@
         "@babel/plugin-syntax-json-strings": "^7.7.4"
       }
     },
+    "@babel/plugin-proposal-nullish-coalescing-operator": {
+      "version": "7.7.4",
+      "resolved": "https://registry.npmjs.org/@babel/plugin-proposal-nullish-coalescing-operator/-/plugin-proposal-nullish-coalescing-operator-7.7.4.tgz",
+      "integrity": "sha512-TbYHmr1Gl1UC7Vo2HVuj/Naci5BEGNZ0AJhzqD2Vpr6QPFWpUmBRLrIDjedzx7/CShq0bRDS2gI4FIs77VHLVQ==",
+      "dev": true,
+      "requires": {
+        "@babel/helper-plugin-utils": "^7.0.0",
+        "@babel/plugin-syntax-nullish-coalescing-operator": "^7.7.4"
+      }
+    },
     "@babel/plugin-proposal-object-rest-spread": {
       "version": "7.7.7",
       "resolved": "https://registry.npmjs.org/@babel/plugin-proposal-object-rest-spread/-/plugin-proposal-object-rest-spread-7.7.7.tgz",
@@ -363,6 +373,16 @@
         "@babel/plugin-syntax-optional-catch-binding": "^7.7.4"
       }
     },
+    "@babel/plugin-proposal-optional-chaining": {
+      "version": "7.7.5",
+      "resolved": "https://registry.npmjs.org/@babel/plugin-proposal-optional-chaining/-/plugin-proposal-optional-chaining-7.7.5.tgz",
+      "integrity": "sha512-sOwFqT8JSchtJeDD+CjmWCaiFoLxY4Ps7NjvwHC/U7l4e9i5pTRNt8nDMIFSOUL+ncFbYSwruHM8WknYItWdXw==",
+      "dev": true,
+      "requires": {
+        "@babel/helper-plugin-utils": "^7.0.0",
+        "@babel/plugin-syntax-optional-chaining": "^7.7.4"
+      }
+    },
     "@babel/plugin-proposal-unicode-property-regex": {
       "version": "7.7.7",
       "resolved": "https://registry.npmjs.org/@babel/plugin-proposal-unicode-property-regex/-/plugin-proposal-unicode-property-regex-7.7.7.tgz",
@@ -418,6 +438,15 @@
         "@babel/helper-plugin-utils": "^7.0.0"
       }
     },
+    "@babel/plugin-syntax-nullish-coalescing-operator": {
+      "version": "7.7.4",
+      "resolved": "https://registry.npmjs.org/@babel/plugin-syntax-nullish-coalescing-operator/-/plugin-syntax-nullish-coalescing-operator-7.7.4.tgz",
+      "integrity": "sha512-XKh/yIRPiQTOeBg0QJjEus5qiSKucKAiApNtO1psqG7D17xmE+X2i5ZqBEuSvo0HRuyPaKaSN/Gy+Ha9KFQolw==",
+      "dev": true,
+      "requires": {
+        "@babel/helper-plugin-utils": "^7.0.0"
+      }
+    },
     "@babel/plugin-syntax-object-rest-spread": {
       "version": "7.7.4",
       "resolved": "https://registry.npmjs.org/@babel/plugin-syntax-object-rest-spread/-/plugin-syntax-object-rest-spread-7.7.4.tgz",
@@ -436,6 +465,15 @@
         "@babel/helper-plugin-utils": "^7.0.0"
       }
     },
+    "@babel/plugin-syntax-optional-chaining": {
+      "version": "7.7.4",
+      "resolved": "https://registry.npmjs.org/@babel/plugin-syntax-optional-chaining/-/plugin-syntax-optional-chaining-7.7.4.tgz",
+      "integrity": "sha512-2MqYD5WjZSbJdUagnJvIdSfkb/ucOC9/1fRJxm7GAxY6YQLWlUvkfxoNbUPcPLHJyetKUDQ4+yyuUyAoc0HriA==",
+      "dev": true,
+      "requires": {
+        "@babel/helper-plugin-utils": "^7.0.0"
+      }
+    },
     "@babel/plugin-syntax-top-level-await": {
       "version": "7.7.4",
       "resolved": "https://registry.npmjs.org/@babel/plugin-syntax-top-level-await/-/plugin-syntax-top-level-await-7.7.4.tgz",
@@ -1051,9 +1089,9 @@
       }
     },
     "@types/json-schema": {
-      "version": "7.0.3",
-      "resolved": "https://registry.npmjs.org/@types/json-schema/-/json-schema-7.0.3.tgz",
-      "integrity": "sha512-Il2DtDVRGDcqjDtE+rF8iqg1CArehSK84HZJCT7AMITlyXRBpuPhqGLDQMowraqqu1coEaimg4ZOqggt6L6L+A==",
+      "version": "7.0.4",
+      "resolved": "https://registry.npmjs.org/@types/json-schema/-/json-schema-7.0.4.tgz",
+      "integrity": "sha512-8+KAKzEvSUdeo+kmqnKrqgeE+LcA0tjYWFY7RPProVYwnqDjukzO+3b6dLD56rYX5TdWejnEOLJYOIeh4CXKuA==",
       "dev": true
     },
     "@types/minimatch": {
@@ -1157,12 +1195,12 @@
       }
     },
     "@typescript-eslint/eslint-plugin": {
-      "version": "2.12.0",
-      "resolved": "https://registry.npmjs.org/@typescript-eslint/eslint-plugin/-/eslint-plugin-2.12.0.tgz",
-      "integrity": "sha512-1t4r9rpLuEwl3hgt90jY18wJHSyb0E3orVL3DaqwmpiSDHmHiSspVsvsFF78BJ/3NNG3qmeso836jpuBWYziAA==",
+      "version": "2.13.0",
+      "resolved": "https://registry.npmjs.org/@typescript-eslint/eslint-plugin/-/eslint-plugin-2.13.0.tgz",
+      "integrity": "sha512-QoiANo0MMGNa8ej/yX3BrW5dZj5d8HYcKiM2fyYUlezECqn8Xc7T/e4EUdiGinn8jhBrn+9X47E9TWaaup3u1g==",
       "dev": true,
       "requires": {
-        "@typescript-eslint/experimental-utils": "2.12.0",
+        "@typescript-eslint/experimental-utils": "2.13.0",
         "eslint-utils": "^1.4.3",
         "functional-red-black-tree": "^1.0.1",
         "regexpp": "^3.0.0",
@@ -1181,13 +1219,13 @@
       }
     },
     "@typescript-eslint/experimental-utils": {
-      "version": "2.12.0",
-      "resolved": "https://registry.npmjs.org/@typescript-eslint/experimental-utils/-/experimental-utils-2.12.0.tgz",
-      "integrity": "sha512-jv4gYpw5N5BrWF3ntROvCuLe1IjRenLy5+U57J24NbPGwZFAjhnM45qpq0nDH1y/AZMb3Br25YiNVwyPbz6RkA==",
+      "version": "2.13.0",
+      "resolved": "https://registry.npmjs.org/@typescript-eslint/experimental-utils/-/experimental-utils-2.13.0.tgz",
+      "integrity": "sha512-+Hss3clwa6aNiC8ZjA45wEm4FutDV5HsVXPl/rDug1THq6gEtOYRGLqS3JlTk7mSnL5TbJz0LpEbzbPnKvY6sw==",
       "dev": true,
       "requires": {
         "@types/json-schema": "^7.0.3",
-        "@typescript-eslint/typescript-estree": "2.12.0",
+        "@typescript-eslint/typescript-estree": "2.13.0",
         "eslint-scope": "^5.0.0"
       },
       "dependencies": {
@@ -1204,21 +1242,21 @@
       }
     },
     "@typescript-eslint/parser": {
-      "version": "2.12.0",
-      "resolved": "https://registry.npmjs.org/@typescript-eslint/parser/-/parser-2.12.0.tgz",
-      "integrity": "sha512-lPdkwpdzxEfjI8TyTzZqPatkrswLSVu4bqUgnB03fHSOwpC7KSerPgJRgIAf11UGNf7HKjJV6oaPZI4AghLU6g==",
+      "version": "2.13.0",
+      "resolved": "https://registry.npmjs.org/@typescript-eslint/parser/-/parser-2.13.0.tgz",
+      "integrity": "sha512-vbDeLr5QRJ1K7x5iRK8J9wuGwR9OVyd1zDAY9XFAQvAosHVjSVbDgkm328ayE6hx2QWVGhwvGaEhedcqAbfQcA==",
       "dev": true,
       "requires": {
         "@types/eslint-visitor-keys": "^1.0.0",
-        "@typescript-eslint/experimental-utils": "2.12.0",
-        "@typescript-eslint/typescript-estree": "2.12.0",
+        "@typescript-eslint/experimental-utils": "2.13.0",
+        "@typescript-eslint/typescript-estree": "2.13.0",
         "eslint-visitor-keys": "^1.1.0"
       }
     },
     "@typescript-eslint/typescript-estree": {
-      "version": "2.12.0",
-      "resolved": "https://registry.npmjs.org/@typescript-eslint/typescript-estree/-/typescript-estree-2.12.0.tgz",
-      "integrity": "sha512-rGehVfjHEn8Frh9UW02ZZIfJs6SIIxIu/K1bbci8rFfDE/1lQ8krIJy5OXOV3DVnNdDPtoiPOdEANkLMrwXbiQ==",
+      "version": "2.13.0",
+      "resolved": "https://registry.npmjs.org/@typescript-eslint/typescript-estree/-/typescript-estree-2.13.0.tgz",
+      "integrity": "sha512-t21Mg5cc8T3ADEUGwDisHLIubgXKjuNRbkpzDMLb7/JMmgCe/gHM9FaaujokLey+gwTuLF5ndSQ7/EfQqrQx4g==",
       "dev": true,
       "requires": {
         "debug": "^4.1.1",
diff --git a/viewer/package.json b/viewer/package.json
index dda1eb4..52ef0d0 100644
--- a/viewer/package.json
+++ b/viewer/package.json
@@ -23,9 +23,11 @@
     "vuex-class-component": "^2.2.1"
   },
   "devDependencies": {
+    "@babel/plugin-proposal-nullish-coalescing-operator": "^7.7.4",
+    "@babel/plugin-proposal-optional-chaining": "^7.7.5",
     "@types/webpack": "^4.4.0",