fix: do not require Content-Secruity-Policy style-src 'unsafe-inline' (#256)

Author: jelhan

src/ResizeSensor.js

@@ -81,6 +81,18 @@
         }
     }
 
+    /**
+     * Apply CSS styles to element.
+     *
+     * @param {HTMLElement} element
+     * @param {Object} style
+     */
+    function setStyle(element, style) {
+        Object.keys(style).forEach(function(key) {
+            element.style[key] = style[key];
+        });
+    }
+
     /**
      * Class for dimension change detection.
      *
@@ -138,18 +150,47 @@
             element.resizeSensor = document.createElement('div');
             element.resizeSensor.dir = 'ltr';
             element.resizeSensor.className = 'resize-sensor';
-            var style = 'pointer-events: none; position: absolute; left: 0px; top: 0px; right: 0; bottom: 0; ' +
-                'overflow: hidden; z-index: -1; visibility: hidden; max-width: 100%;';
-            var styleChild = 'position: absolute; left: 0; top: 0; transition: 0s;';
-
-            element.resizeSensor.style.cssText = style;
-            element.resizeSensor.innerHTML =
-                '<div class="resize-sensor-expand" style="' + style + '">' +
-                    '<div style="' + styleChild + '"></div>' +
-                '</div>' +
-                '<div class="resize-sensor-shrink" style="' + style + '">' +
-                    '<div style="' + styleChild + ' width: 200%; height: 200%"></div>' +
-                '</div>';
+
+            var style = {
+                pointerEvents: 'none',
+                position: 'absolute',
+                left: '0px',
+                top: '0px',
+                right: '0px',
+                bottom: '0px',
+                overflow: 'hidden',
+                zIndex: '-1',
+                visibility: 'hidden',
+                maxWidth: '100%'
+            };
+            var styleChild = {
+                position: 'absolute',
+                left: '0px',
+                top: '0px',
+                transition: '0s',
+            };
+
+            setStyle(element.resizeSensor, style);
+
+            var expand = document.createElement('div');
+            expand.className = 'resize-sensor-expand';
+            setStyle(expand, style);
+
+            var expandChild = document.createElement('div');
+            setStyle(expandChild, styleChild);
+            expand.appendChild(expandChild);
+
+            var shrink = document.createElement('div');
+            shrink.className = 'resize-sensor-shrink';
+            setStyle(shrink, style);
+
+            var shrinkChild = document.createElement('div');
+            setStyle(shrinkChild, styleChild);
+            setStyle(shrinkChild, { width: '200%', height: '200%' });
+            shrink.appendChild(shrinkChild);
+
+            element.resizeSensor.appendChild(expand);
+            element.resizeSensor.appendChild(shrink);
             element.appendChild(element.resizeSensor);
 
             var computedStyle = window.getComputedStyle(element);
@@ -158,9 +199,6 @@
                 element.style.position = 'relative';
             }
 
-            var expand = element.resizeSensor.childNodes[0];
-            var expandChild = expand.childNodes[0];
-            var shrink = element.resizeSensor.childNodes[1];
             var dirty, rafId;
             var size = getElementSize(element);
             var lastWidth = size.width;