Fix some lint errors

.eslintrc.js

@@ -25,8 +25,6 @@ module.exports = {
     'plugin:react/recommended',
   ],
   rules: {
-    'no-var': 'off',
-    'prefer-const': 'off',
     'no-case-declarations': 'off',
     'prefer-spread': 'off',
     'no-extra-boolean-cast': 'off',

src/app.tsx

@@ -150,7 +150,7 @@ function getArguments(location: H.Location<any>): Arguments {
   const hash = getParam('file');
   const url = getParam('url');
   const embedded = getParam('embedded') === 'true'; // False by default.
-  var sourceSpec: DataSourceSpec | undefined = undefined;
+  let sourceSpec: DataSourceSpec | undefined = undefined;
   if (staticUrl) {
     sourceSpec = {
       source: DataSourceEnum.GEDCOM_URL,
@@ -267,9 +267,9 @@ export function App() {
     if (data === undefined) {
       return;
     }
-    let shouldHideIds = config.id === Ids.HIDE;
-    let shouldHideSex = config.sex === Sex.HIDE;
-    let indiMap = idToIndiMap(data.chartData);
+    const shouldHideIds = config.id === Ids.HIDE;
+    const shouldHideSex = config.sex === Sex.HIDE;
+    const indiMap = idToIndiMap(data.chartData);
     indiMap.forEach((indi) => {
       indi.hideId = shouldHideIds;
       indi.hideSex = shouldHideSex;

src/datasource/load_data.ts

@@ -54,7 +54,7 @@ async function loadGedzip(
 
   let gedcom = undefined;
   const images = new Map<string, string>();
-  for (let fileName of Object.keys(unzipped)) {
+  for (const fileName of Object.keys(unzipped)) {
     if (fileName.endsWith('.ged')) {
       if (gedcom) {
         console.warn('Multiple GEDCOM files found in zip archive.');

src/sidepanel/details/details.tsx

@@ -60,13 +60,13 @@ function attributeDetails(entry: GedcomEntry) {
     return null;
   }
 
-  let attributeName = entry.tree
+  const attributeName = entry.tree
       .filter((subentry) => subentry.tag === 'TYPE')
       .flatMap((type) => getData(type))
       .join()
       .trim();
 
-  let attributeValue = getData(entry).join(' ').trim();
+  const attributeValue = getData(entry).join(' ').trim();
   if(attributeName) {
     return (
         <>