Enable some more eslint checks

app/assets/javascripts/leaflet.map.js

@@ -44,7 +44,7 @@ L.OSM.Map = L.Map.extend({
     }
 
     this.baseLayers.push(new L.OSM.HOT({
-      attribution: copyright + ". Tiles style by <a href='https://www.hotosm.org/' target='_blank'>Humanitarian OpenStreetMap Team</a>" + " hosted by <a href='https://openstreetmap.fr/' target='_blank'>OpenStreetMap France</a>",
+      attribution: copyright + ". Tiles style by <a href='https://www.hotosm.org/' target='_blank'>Humanitarian OpenStreetMap Team</a> hosted by <a href='https://openstreetmap.fr/' target='_blank'>OpenStreetMap France</a>",
       code: "H",
       keyid: "hot",
       name: I18n.t("javascripts.map.base.hot")
@@ -136,9 +136,10 @@ L.OSM.Map = L.Map.extend({
       // done in two parts. each of the parts c1/c2 has 30 bits of the total in it
       // and drops the last 4 bits of the full 64 bit Morton code.
       c1 = interlace(x >>> 17, y >>> 17), c2 = interlace((x >>> 2) & 0x7fff, (y >>> 2) & 0x7fff),
-      digit;
+      digit,
+      i;
 
-    for (var i = 0; i < Math.ceil((zoom + 8) / 3.0) && i < 5; ++i) {
+    for (i = 0; i < Math.ceil((zoom + 8) / 3.0) && i < 5; ++i) {
       digit = (c1 >> (24 - 6 * i)) & 0x3f;
       str += char_array.charAt(digit);
     }

app/assets/javascripts/leaflet.share.js

@@ -313,7 +313,7 @@ L.OSM.share = function (options) {
         "\"": """,
         "'": "'"
       };
-      return string === null ? "" : (string + "").replace(/[&<>"']/g, function(match) {
+      return string === null ? "" : String(string).replace(/[&<>"']/g, function(match) {
         return htmlEscapes[match];
       });
     }

config/eslint.json

@@ -17,14 +17,22 @@
     "updateLinks": "readonly"
   },
   "rules": {
+    "accessor-pairs": "error",
+    "array-callback-return": "error",
+    "block-scoped-var": "error",
     "dot-notation": "error",
     "eqeqeq": ["error", "smart"],
     "keyword-spacing": "error",
+    "no-alert": "warn",
     "no-caller": "error",
     "no-div-regex": "error",
+    "no-eval": "error",
     "no-extend-native": "error",
     "no-extra-bind": "error",
+    "no-extra-label": "error",
     "no-floating-decimal": "error",
+    "no-implicit-coercion": "warn",
+    "no-implicit-globals": "warn",
     "no-implied-eval": "error",
     "no-iterator": "error",
     "no-labels": "error",
@@ -44,9 +52,13 @@
     "no-shadow-restricted-names": "error",
     "no-throw-literal": "error",
     "no-trailing-spaces": "error",
+    "no-unmodified-loop-condition": "error",
     "no-unneeded-ternary": "error",
     "no-unused-expressions": "off",
     "no-unused-vars": "error",
+    "no-useless-call": "error",
+    "no-useless-concat": "error",
+    "no-useless-return": "error",
     "no-use-before-define": ["error", {"functions": false}],
     "no-void": "error",
     "no-warning-comments": "warn",
@@ -56,6 +68,8 @@
     "semi": ["error", "always"],
     "semi-spacing": "error",
     "space-unary-ops": "error",
-    "wrap-regex": "off"
+    "wrap-iife": "error",
+    "wrap-regex": "error",
+    "yoda": "error"
   }
 }