[Calendar] Remove promise based loading in favor of loading prop

.gitignore

@@ -36,3 +36,5 @@ coverage
 # editors
 .vs
 .DS_Store
+
+.vercel

docs/.gitignore

@@ -0,0 +1 @@
+.vercel

docs/babel.config.js

@@ -7,6 +7,9 @@ module.exports = {
       'babel-plugin-module-resolver',
       {
         root: ['./'],
+        alias: {
+          '@material-ui/pickers/CalendarSkeleton': '@material-ui/pickers/src/CalendarSkeleton',
+        },
       },
     ],
   ],

docs/fakeApi/randomDate.ts

@@ -0,0 +1,32 @@
+import { getDaysInMonth, isValid } from 'date-fns';
+import { NowRequest, NowResponse } from '@now/node';
+
+function getRandomNumber(min: number, max: number) {
+  return Math.round(Math.random() * (max - min) + min);
+}
+
+export default function(req: NowRequest, res: NowResponse) {
+  const { month } = req.query;
+
+  if (!month || typeof month !== 'string') {
+    res.status(400);
+    return res.json({
+      reason: 'month query param is required',
+    });
+  }
+
+  const date = new Date(month);
+  if (!isValid(date)) {
+    res.status(422);
+    return res.json({
+      reason: 'cannot parse month value',
+    });
+  }
+
+  setTimeout(() => {
+    const daysInMonth = getDaysInMonth(date);
+    const daysToHighlight = [1, 2, 3].map(_ => getRandomNumber(1, daysInMonth));
+
+    res.json({ daysToHighlight });
+  }, 500); // fake some long work
+}

docs/package.json

@@ -23,7 +23,9 @@
     "@mapbox/rehype-prism": "^0.4.0",
     "@material-ui/core": "^4.9.14",
     "@material-ui/icons": "^4.9.1",
+    "@material-ui/lab": "^4.0.0-alpha.54",
     "@material-ui/pickers": "^4.0.0-alpha.1",
+    "@now/node": "^1.6.1",
     "@types/fuzzy-search": "^2.1.0",
     "@types/isomorphic-fetch": "^0.0.35",
     "@types/jss": "^10.0.0",
@@ -57,6 +59,7 @@
     "next-images": "^1.4.0",
     "next-transpile-modules": "^2.0.0",
     "notistack": "^0.9.11",
+    "now": "^19.0.1",
     "prismjs": "^1.20.0",
     "raw-loader": "^1.0.0",
     "react": "^16.13.0",

docs/pages/demo/datepicker/ServerRequest.example.jsx

@@ -1,41 +1,61 @@
-import React, { useState } from 'react';
+import * as React from 'react';
 import { Badge } from '@material-ui/core';
 import { TextField } from '@material-ui/core';
 import { DatePicker, Day } from '@material-ui/pickers';
 import { makeJSDateObject } from '../../../utils/helpers';
-
-function getRandomNumber(min, max) {
-  return Math.round(Math.random() * (max - min) + min);
-}
+import { CalendarSkeleton } from '@material-ui/pickers/CalendarSkeleton';
 
 function ServerRequest() {
-  const [selectedDays, setSelectedDays] = useState([1, 2, 15]);
-  const [selectedDate, handleDateChange] = useState(new Date());
-
-  const handleMonthChange = async () => {
-    // just select random days to simulate server side based data
-    return new Promise(resolve => {
-      setTimeout(() => {
-        setSelectedDays([1, 2, 3].map(() => getRandomNumber(1, 28)));
-        resolve();
-      }, 1000);
-    });
+  const requestAbortController = React.useRef(null);
+  const [highlightedDays, setHighlightedDays] = React.useState([1, 2, 15]);
+  const [selectedDate, handleDateChange] = React.useState(new Date());
+
+  React.useEffect(() => {
+    // abort request on unmount
+    return () => requestAbortController.current?.abort();
+  }, []);
+
+  const handleMonthChange = date => {
+    if (requestAbortController.current) {
+      // make sure that you are aborting useless requests
+      // because it is possible to switch between months pretty quickly
+      requestAbortController.current.abort();
+    }
+
+    setHighlightedDays(null);
+
+    const controller = new AbortController();
+    fetch(`/fakeApi/randomDate?month=${date.toString()}`, {
+      signal: controller.signal,
+    })
+      .then(res => res.json())
+      .then(({ daysToHighlight }) => setHighlightedDays(daysToHighlight))
+      .catch(() => console.log('Wow, you are switching months too quickly 🐕'));
+
+    requestAbortController.current = controller;
   };
 
   return (
     <>
       <DatePicker
         value={selectedDate}
+        loading={highlightedDays === null}
         onChange={date => handleDateChange(date)}
         onMonthChange={handleMonthChange}
+        // loading
         renderInput={props => <TextField {...props} />}
+        renderLoading={() => <CalendarSkeleton />}
         renderDay={(day, selectedDate, DayComponentProps) => {
           const date = makeJSDateObject(day); // skip this step, it is required to support date libs
           const isSelected =
-            DayComponentProps.inCurrentMonth && selectedDays.includes(date.getDate());
+            DayComponentProps.inCurrentMonth && highlightedDays.includes(date.getDate());
 
           return (
-            <Badge overlap="circle" badgeContent={isSelected ? '🌚' : undefined}>
+            <Badge
+              key={date.toString()}
+              overlap="circle"
+              badgeContent={isSelected ? '🌚' : undefined}
+            >
               <Day {...DayComponentProps} />
             </Badge>
           );

docs/pages/demo/datepicker/index.mdx

@@ -68,9 +68,10 @@ You can leverage our internal [Day](/api/Day) component, and render it in defaul
 
 #### Dynamic data
 
-Sometimes it's required to display additional info right in the calendar.
-For this just return `Promise` in `onMonthChange`.
+Sometimes it's required to display additional info right in the calendar. Here is an example of prefetching
+and displaying server side data using `onMonthChange`, `loading` and `renderDay` props.
 
+<!-- In order to make this example functional, make sure you are running docs using `yarn now dev` from root -->
 <Example source={ServerRequest} />
 
 #### Components API