[Fix] DateInput: isTouchDevice should only be determined in componentDidMount

.eslintrc

@@ -9,5 +9,6 @@
   "rules": {
     "no-mixed-operators": [2, { "allowSamePrecedence": true }],
     "jsx-a11y/no-static-element-interactions": 1, // TODO: enable
+    "react/no-did-mount-set-state": 0, // necessary for server-rendering
   }
 }

src/components/DateInput.jsx

@@ -42,12 +42,15 @@ export default class DateInput extends React.Component {
     super(props);
     this.state = {
       dateString: '',
+      isTouchDevice: false,
     };
 
     this.onChange = this.onChange.bind(this);
     this.onKeyDown = this.onKeyDown.bind(this);
+  }
 
-    this.isTouchDevice = isTouchDevice();
+  componentDidMount() {
+    this.setState({ isTouchDevice: isTouchDevice() });
   }
 
   componentWillReceiveProps(nextProps) {
@@ -89,7 +92,10 @@ export default class DateInput extends React.Component {
   }
 
   render() {
-    const { dateString } = this.state;
+    const {
+      dateString,
+      isTouchDevice: isTouch,
+    } = this.state;
     const {
       id,
       placeholder,
@@ -128,7 +134,7 @@ export default class DateInput extends React.Component {
           placeholder={placeholder}
           autoComplete="off"
           disabled={disabled}
-          readOnly={this.isTouchDevice}
+          readOnly={isTouch}
           required={required}
           aria-describedby={screenReaderMessage && screenReaderMessageId}
         />

test/_helpers/withTouchSupport.js

@@ -0,0 +1,13 @@
+import wrap from 'mocha-wrap';
+import withGlobal from 'mocha-wrap/withGlobal';
+import withOverride from 'mocha-wrap/withOverride';
+
+function withTouchSupport() {
+  return this
+    .use(withGlobal, 'window', () => (typeof window !== 'undefined' ? window : {}))
+    .use(withOverride, () => window, 'ontouchstart', () => window.ontouchstart || (() => {}))
+    .use(withGlobal, 'navigator', () => (typeof navigator !== 'undefined' ? navigator : {}))
+    .use(withOverride, () => navigator, 'maxTouchPoints', () => navigator.maxTouchPoints || true);
+}
+
+wrap.register(withTouchSupport);

test/components/DateInput_spec.jsx

@@ -2,6 +2,7 @@ import React from 'react';
 import { expect } from 'chai';
 import { shallow } from 'enzyme';
 import sinon from 'sinon-sandbox';
+import wrap from 'mocha-wrap';
 
 import DateInput from '../../src/components/DateInput';
 
@@ -206,4 +207,31 @@ describe('DateInput', () => {
       expect(onKeyDownTabStub.callCount).to.equal(0);
     });
   });
+
+  describe('touch device detection', () => {
+    it('indicates no touch support on the client', () => {
+      const wrapper = shallow(<DateInput id="date" />);
+      expect(wrapper.state()).to.contain.keys({ isTouchDevice: false });
+    });
+
+    it('does not set readOnly when not a touch device', () => {
+      const wrapper = shallow(<DateInput id="date" />);
+      expect(!!wrapper.find('input').prop('readOnly')).to.equal(false);
+    });
+
+    it('sets readOnly when a touch device', () => {
+      const wrapper = shallow(<DateInput id="date" />);
+      wrapper.setState({ isTouchDevice: true });
+      wrapper.update();
+      expect(!!wrapper.find('input').prop('readOnly')).to.equal(true);
+    });
+
+    wrap()
+    .withTouchSupport()
+    .it('sets isTouchDevice state when is a touch device', () => {
+      const wrapper = shallow(<DateInput id="date" />);
+      wrapper.instance().componentDidMount();
+      expect(wrapper.state()).to.contain.keys({ isTouchDevice: true });
+    });
+  });
 });