Travis TypeScript Compiler Checking (#263)

* add typescript compliler check to travis

* fix existing typescript compiler errors

.travis.yml

@@ -16,3 +16,4 @@ notifications:
 script:
 - npm run test
 - npm run tslint
+- tsc --noEmit

common/components/ui/Dropdown.tsx

@@ -3,7 +3,7 @@ import classnames from 'classnames';
 import DropdownShell from './DropdownShell';
 
 interface Props<T> {
-  value: T;
+  value: T | undefined;
   options: T[];
   ariaLabel: string;
   label?: string;

common/components/ui/SimpleDropdown.tsx

@@ -2,7 +2,7 @@ import React, { Component } from 'react';
 import Dropdown from './Dropdown';
 
 interface Props {
-  value?: string;
+  value: string | undefined;
   options: string[];
   ariaLabel?: string;
   onChange(value: string): void;
@@ -19,7 +19,7 @@ export default class SimpleDropdown extends Component<Props, void> {
         options={options}
         value={value}
         onChange={onChange}
-        ariaLabel={ariaLabel || "dropdown"}
+        ariaLabel={ariaLabel || 'dropdown'}
       />
     );
   }

common/containers/Tabs/SendTransaction/components/UnitDropdown.tsx

@@ -1,31 +1,38 @@
 import React from 'react';
-import SimpleDropdown from 'components/ui/SimpleDropdown';
+import Dropdown from 'components/ui/Dropdown';
 
 interface UnitDropdownProps {
   value: string;
   options: string[];
   onChange?(value: string): void;
 }
+
 interface State {
   expanded: boolean;
 }
+
+const initialState = {
+  expanded: false
+};
+
 export default class UnitDropdown extends React.Component<
   UnitDropdownProps,
   State
 > {
-  public state = {
-    expanded: false
-  };
+  public state: State = initialState;
 
   public render() {
     const { value, options } = this.props;
 
+    const StringDropdown = Dropdown as new () => Dropdown<string>;
+
     return (
       <div className="input-group-btn">
-        <SimpleDropdown
+        <StringDropdown
+          options={options}
           value={value}
           onChange={this.onChange}
-          options={options}
+          ariaLabel={'dropdown'}
         />
       </div>
     );