some improvements

README.md

@@ -143,3 +143,11 @@ A function that triggers when text state has updated.
 #### `onFinish: () => void`(optional)
 
 A function that triggers when animation completes.
+
+#### `startAt: number`(optional, default to `0`)
+
+Timeout in milliseconds to start animation after.
+
+#### `initialValue: number`(optional, default to `0`)
+
+A value to start animation from

dist/index.d.ts

@@ -0,0 +1,49 @@
+declare module 'react-native-animate-number' {
+  export interface IAnimateNumberProps {
+    /**
+     * The value of AnimateNumber component.
+     */
+    value: number;
+    /**
+     * Set this property to force the component's value increase/decrease by this number.
+     */
+    countBy?: number;
+    /**
+     * Base interval of each animation frame, in ms. Default: `14`
+     */
+    interval?: number;
+    /**
+     * Set total frame number of animation, say, if interval is 14 and steps is 30, the animation will take 14x30ms to finish when it uses linear timing function.
+     * Default: `45`
+     */
+    steps?: number;
+    /**
+     * Custom timing function or use a default timing function.
+     * Default: `linear`
+     */
+    timing?: 'linear' | 'easeOut' | 'easeIn' | ((interval: number, progress: number) => number);
+    /**
+     * This prop accepts a function which returns a string as displayed value.
+     */
+    formatter?: (value: number) => string;
+    /**
+     * A function that triggers when text state has updated.
+     * @param currentValue current frame's value
+     * @param endValue value from props.value
+     */
+    onProgress?: (currentValue: number, endValue: number) => void;
+    /**
+     * A function that triggers when animation completes.
+     */
+    onFinish?: (value: number, formattedValue: number) => void;
+    /**
+     * Timeout in milliseconds to start animation after. Default: `0`
+     */
+    startAt?: number;
+    /**
+     * A value to start animation from. Default: `0`
+     */
+    initialValue?: number;
+  }
+  export default class AnimateNumber extends React.Component<IAnimateNumberProps> {}
+}

dist/index.js

@@ -6,10 +6,7 @@
 // @flow
 
 import React, { Component } from 'react';
-import {
-  Text,
-  View
-} from 'react-native';
+import { Text } from 'react-native';
 import Timer from 'react-timer-mixin';
 
 const HALF_RAD = Math.PI/2
@@ -99,7 +96,7 @@ export default class AnimateNumber extends Component {
       , this.props.startAt != null ? this.props.startAt : 0);
   }
 
-  componentWillUpdate(nextProps, nextState) {
+  UNSAFE_componentWillUpdate(nextProps) {
 
     // check if start an animation
     if(this.props.value !== nextProps.value) {

package.json

@@ -1,6 +1,6 @@
 {
   "name": "react-native-animate-number",
-  "version": "0.1.2",
+  "version": "0.1.3",
   "description": "",
   "main": "index.js",
   "scripts": {