Migration to typescript: first step

Add vue cli typescript support
Rename .js to .ts
Use class and annotations in App and NavBar
Add tslint

js/get_union_json.ts

@@ -0,0 +1,38 @@
+const fetch = require('node-fetch');
+const fs = require('fs');
+
+fetch(`http://localhost:4000/graphiql`, {
+  method: 'POST',
+  headers: { 'Content-Type': 'application/json' },
+  body: JSON.stringify({
+    variables: {},
+    query: `
+      {
+        __schema {
+          types {
+            kind
+            name
+            possibleTypes {
+              name
+            }
+          }
+        }
+      }
+    `,
+  }),
+})
+  .then(result => result.json())
+  .then(result => {
+    // here we're filtering out any type information unrelated to unions or interfaces
+    const filteredData = result.data.__schema.types.filter(
+      type => type.possibleTypes !== null,
+    );
+    result.data.__schema.types = filteredData;
+    fs.writeFile('./fragmentTypes.json', JSON.stringify(result.data), err => {
+      if (err) {
+        console.error('Error writing fragmentTypes file', err);
+      } else {
+        console.log('Fragment types successfully extracted!');
+      }
+    });
+  });