diff --git a/README.md b/README.md
index 968c9a8..9b08bde 100644
--- a/README.md
+++ b/README.md
@@ -12,11 +12,12 @@ yarn add react-transition-collapse
 
 ### Usage
 
-ReactTransitionCollapse takes three props:
+ReactTransitionCollapse takes these props:
 ```
-expanded: boolean
-duration: number | string // number of milliseconds
 children: Element
+duration: number | string // number of milliseconds
+expanded: boolean
+animationType: 'scale' | 'translate' // which css transform should be applied to animate the transition
 ```
 
 #### Full example
diff --git a/src/react-transition-collapse.tsx b/src/react-transition-collapse.tsx
index 4b9e66c..c411922 100644
--- a/src/react-transition-collapse.tsx
+++ b/src/react-transition-collapse.tsx
@@ -60,7 +60,7 @@ class ReactTransitionCollapse extends React.PureComponent<transitionProps> {
   reMeasure = () => {
     let timeout: NodeJS.Timeout
     return this.getListener(() => {
-      if (!this.wrapperEl || !this.wrapperEl.contains(this.innerEl)) {
+      if (!this.wrapperEl || !this.innerEl || !this.wrapperEl.contains(this.innerEl)) {
         return
       }
       clearTimeout(timeout)
@@ -101,7 +101,7 @@ class ReactTransitionCollapse extends React.PureComponent<transitionProps> {
         this.wrapperEl.appendChild(this.innerEl)
         const reexec = () =>
           requestAnimationFrame(() => {
-            if (this.wrapperEl && this.wrapperEl.contains(this.innerEl)) {
+            if (this.wrapperEl && this.innerEl && this.wrapperEl.contains(this.innerEl)) {
               this.measure(this.innerEl)
               this.updateInnerHeight(this.height)
             } else {