added ability to set the start state and pass in a callback function

src/CheckBox.jsx

@@ -7,21 +7,34 @@ import { inputProps } from './utils/asInput';
 class CheckBox extends React.Component {
   constructor(props) {
     super(props);
-    this.state = {
-      pressed: 'false',
-    };
+    if (props.checked === 'true') {
+      this.state = {
+        pressed: props.checked,
+        checked: true,
+      };
+    } else {
+      this.state = {
+        pressed: props.checked,
+        checked: false,
+      };
+    }
   }
 
   handleClick() {
     if (this.state.pressed === 'true') {
       this.setState({
         pressed: 'false',
+        checked: false,
       });
     } else {
       this.setState({
         pressed: 'true',
+        checked: true,
       });
     }
+    if (this.props.fun) {
+      this.props.fun();
+    }
   }
 
 
@@ -32,14 +45,15 @@ class CheckBox extends React.Component {
       <form>
         <label htmlFor={props.checkLabel} className="form-check-label">
           <input
+            name={props.name}
             type="checkbox"
+            defaultChecked={this.state.checked}
             className="form-check-input"
-            name={props.name}
             aria-describedby={props.describedby}
             aria-checked={this.state.pressed}
             tabIndex="0"
             onClick={() => this.handleClick()}
-            disabled={props.disabled}
+            disabled={props.disable}
           />
           {props.checkLabel}
         </label>

stories/index.jsx

@@ -133,6 +133,7 @@ storiesOf('CheckBox', module)
       label="CheckBox"
       describedBy="checkbox"
       checkLabel="check me out!"
+      checked="false"
     />
   ))
   .add('disabled', () => (
@@ -141,6 +142,16 @@ storiesOf('CheckBox', module)
       label="CheckBox"
       describedBy="checkbox"
       checkLabel="you cannot check me out"
-      disabled="true"
+      checked="false"
+      disable="true"
+    />
+  ))
+  .add('default checked', () => (
+    <CheckBox
+      name="checkbox"
+      label="CheckBox"
+      describedBy="checkbox"
+      checkLabel="(un)check me out"
+      checked="true"
     />
   ));