feat: Create Typescript definitions (#51)

* [Typescript] Created Typescript definitions

* Update index.d.ts

Author: franklixuefei

index.d.ts

@@ -0,0 +1,28 @@
+import * as React from 'react';
+  
+export interface Dimensions {
+  top: number;
+  right: number;
+  bottom: number;
+  left: number;
+  width: number;
+  height: number;
+}
+
+export interface ContainerDimensionsProps {
+  /**
+   * Can either be a function that's responsible for rendering children.
+   * This function should implement the following signature:
+   * ({ height, width }) => PropTypes.element
+   * Or a React element, with width and height injected into its props.
+   */
+  children: ((props: Dimensions) => React.ReactNode) | React.ReactNode;
+}
+
+/**
+ * Component that automatically adjusts the width and height of a single child.
+ * Child component should not be declared as a child but should rather be specified by a `ChildComponent` property.
+ * All other properties will be passed through to the child component.
+ */
+declare const ContainerDimensions: React.ComponentType<ContainerDimensionsProps>;
+export default ContainerDimensions;