feat(setRootNode): save call to getComputedStyle if root node is unch…

…anged
researchgate · Nov 1, 2017 · 80659dd · 80659dd
1 parent f5317d8
commit 80659dd
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Showing 4 changed files with 15 additions and 10 deletions.
diff --git a/package.json b/package.json
@@ -28,7 +28,6 @@
     "eslint-plugin-import": "^2.7.0",
     "eslint-plugin-prettier": "^2.3.0",
     "eslint-plugin-react": "^7.3.0",
-    "flow-bin": "^0.57.1",
     "husky": "^0.14.3",
     "intersection-observer": "^0.4.2",
     "jest": "^21.0.1",

diff --git a/src/List.js b/src/List.js
@@ -49,9 +49,13 @@ export default class List extends React.PureComponent {
     }
 
     setRef = callback => {
+        let prevRootNode;
         this.setRootNode = node => {
-            const overflow = window.getComputedStyle(node)[AXIS_CSS_MAP[this.props.axis]];
-            callback(['auto', 'scroll', 'overlay'].includes(overflow) ? node : null);
+            if (node !== prevRootNode) {
+                prevRootNode = node;
+                const overflow = window.getComputedStyle(node)[AXIS_CSS_MAP[this.props.axis]];
+                callback(['auto', 'scroll', 'overlay'].indexOf(overflow) !== -1 ? node : null);
+            }
         };
     };
 

diff --git a/src/__tests__/List.spec.js b/src/__tests__/List.spec.js
@@ -139,6 +139,12 @@ describe('setRootNode', () => {
         createTree({ currentLength: 20 });
         expect(mockCallback).toBeCalledWith(null);
     });
+
+    test('having same root node prevents call getComputedStyle', () => {
+        const tree = createTree({ currentLength: 20 });
+        tree.getInstance().setRootNode(target);
+        expect(window.getComputedStyle).toHaveBeenCalledTimes(1);
+    });
 });
 
 describe('handleUpdate', () => {

diff --git a/yarn.lock b/yarn.lock
@@ -31,9 +31,9 @@
   dependencies:
     "@researchgate/eslint-config-rg-base" "^1.0.0"
 
-"@researchgate/react-intersection-observer@^0.3.1":
-  version "0.3.1"
-  resolved "https://registry.yarnpkg.com/@researchgate/react-intersection-observer/-/react-intersection-observer-0.3.1.tgz#189e32c85d0b3a70e12d8408aa52e89da4e8bc85"
+"@researchgate/react-intersection-observer@^0.4.0":
+  version "0.4.0"
+  resolved "https://registry.yarnpkg.com/@researchgate/react-intersection-observer/-/react-intersection-observer-0.4.0.tgz#703af3398ea327ba9633718582c528b95da70ef2"
   dependencies:
     invariant "^2.2.2"
     prop-types "^15.5.10"
@@ -3247,10 +3247,6 @@ flatten@^1.0.2:
   version "1.0.2"
   resolved "https://registry.yarnpkg.com/flatten/-/flatten-1.0.2.tgz#dae46a9d78fbe25292258cc1e780a41d95c03782"
 
-flow-bin@^0.56.0:
-  version "0.56.0"
-  resolved "https://registry.yarnpkg.com/flow-bin/-/flow-bin-0.56.0.tgz#ce43092203a344ba9bf63c0cabe95d95145f6cad"
-
 for-in@^1.0.1:
   version "1.0.2"
   resolved "https://registry.yarnpkg.com/for-in/-/for-in-1.0.2.tgz#81068d295a8142ec0ac726c6e2200c30fb6d5e80"