fix stickySectionHeader re-render issue

Close facebook#13500

Author: nihgwu

Libraries/Components/ScrollView/ScrollViewStickyHeader.js

@@ -61,8 +61,9 @@ class ScrollViewStickyHeader extends React.Component {
 
   render() {
     const {measured, layoutHeight, layoutY, nextHeaderLayoutY} = this.state;
+    const inputRange: Array<number> = [-1, 0];
+    const outputRange: Array<number> = [0, 0];
 
-    let translateY;
     if (measured) {
       // The interpolation looks like:
       // - Negative scroll: no translation
@@ -74,8 +75,8 @@ class ScrollViewStickyHeader extends React.Component {
       // header to continue scrolling up and make room for the next sticky header.
       // In the case that there is no next header just translate equally to
       // scroll indefinetly.
-      const inputRange = [-1, 0, layoutY];
-      const outputRange: Array<number> = [0, 0, 0];
+      inputRange.push(layoutY);
+      outputRange.push(0);
       // Sometimes headers jump around so we make sure we don't violate the monotonic inputRange
       // condition.
       const collisionPoint = (nextHeaderLayoutY || 0) - layoutHeight;
@@ -86,14 +87,12 @@ class ScrollViewStickyHeader extends React.Component {
         inputRange.push(layoutY + 1);
         outputRange.push(1);
       }
-      translateY = this.props.scrollAnimatedValue.interpolate({
-        inputRange,
-        outputRange,
-      });
-    } else {
-      translateY = 0;
     }
 
+    const translateY = this.props.scrollAnimatedValue.interpolate({
+      inputRange,
+      outputRange,
+    });
     const child = React.Children.only(this.props.children);
 
     return (