upgrade eslint and associated fixes

don't keep ie() by the way

src/common/browser.js

@@ -30,7 +30,6 @@ const svg = document.createElementNS(NS.SVG, 'svg');
 const isOpera_ = Boolean(window.opera);
 const isWebkit_ = userAgent.includes('AppleWebKit');
 const isGecko_ = userAgent.includes('Gecko/');
-const isIE_ = userAgent.includes('MSIE');
 const isChrome_ = userAgent.includes('Chrome/');
 const isWindows_ = userAgent.includes('Windows');
 const isMac_ = userAgent.includes('Macintosh');
@@ -165,11 +164,6 @@ export const isWebkit = () => isWebkit_;
  * @returns {boolean}
 */
 export const isGecko = () => isGecko_;
-/**
- * @function module:browser.isIE
- * @returns {boolean}
-*/
-export const isIE = () => isIE_;
 /**
  * @function module:browser.isChrome
  * @returns {boolean}

src/common/units.js

@@ -230,13 +230,8 @@ export const convertAttrs = function (element) {
   for (let i = 0; i < len; i++) {
     const attr = attrs[i];
     const cur = element.getAttribute(attr);
-    if (cur) {
-      if (!isNaN(cur)) {
-        element.setAttribute(attr, (cur / typeMap_[unit]) + unit);
-      }
-      // else {
-      // Convert existing?
-      // }
+    if (cur && !isNaN(cur)) {
+      element.setAttribute(attr, (cur / typeMap_[unit]) + unit);
     }
   }
 };

src/common/utilities.js

@@ -679,10 +679,8 @@ export const getBBox = function (elem) {
       } else {
         // Check if element is child of a foreignObject
         const fo = $(selected).closest('foreignObject');
-        if (fo.length) {
-          if (fo[0].getBBox) {
-            ret = fo[0].getBBox();
-          }
+        if (fo.length && fo[0].getBBox) {
+          ret = fo[0].getBBox();
         }
       }
     }