Develop Reference

How to disable list of dates in MUI date picker

I want to disable MUI date picker future dates (only selected dates not all future dates)
I am getting array of dates from API which needs to be disabled from date picker.
Assume that below blackoutDates are what i am getting from API. So how to disable those dates ?
Below is my code
const getDisabledDates = () => {
let blackoutDates = {[
"2022-03-01",
"2022-03-08"
"2022-04-13",
"2022-05-22"
]}
}
<DatePicker
disablePast
value={checkout.rideDate}
shouldDisableDate={getDisabledDates}
onChange={(newValue) => {
dispatch(setRideDate(newValue?.toISOString().split('T')[0]))
}}
renderInput={(params) => <TextField className={classes.datePickerStyle} {...params}/>}
/>

shouldDisableDate is a function with the current date in param. So you need to compare this with your array, to enable / disable the date
const shouldDisableDate= date => {
let blackoutDates = {[
"2022-03-01",
"2022-03-08"
"2022-04-13",
"2022-05-22"
]}
return blackoutDates.includes(date);
}
This is an exemple, as your date is of type Date whereas your array contains strings. So you'll need to convert the date to a YYYY-MM-DD string first, using your prefered way :)

Handler prop shouldDisableDate passes a date argument to the function you provide. So, your function could look like:
const getDisabledDates = (date) => {
let blackoutDates = [
"2022-03-01",
"2022-03-08"
"2022-04-13",
"2022-05-22"
];
// check `date` object against blackoutDates.
// return true | false
}
Keep in mind that the date parameter is a vanilla Date object.
More info at MUI documentation. In the example, you can see how a function isWeekend is passed to a prop shouldDisableDate. According to date-fns documentation this function accepts the date object. I suggest You play around in the demo that MUI provides.

Array inside useEffect to use in if Statement

I'm trying to use an if statement in my code where I want it to 'open' a Calendar Box if the date of today has occurred as well as for the past days of my calendar to open.
Here is my code where I'm using an useEffect to post it on loading the React Component:
// Call on post method via axios
useEffect(async () => {
console.log(daysData);
const daysDay = daysData.map((day) => day.day);
console.log(daysDay);
if (date + 1 >= daysDay) {
// Url where to post
await axios.post(`http://localhost:5001/open/chocolate`, {
day: date,
});
alert('New day is available to eat!');
}
setOpenCalendarBox('');
}, []);
I'm trying to get an array I've initiated a few lines above of the useEffect function (daysData) and I want the value of the 'day' item inside of the objects inside of the array and then compare the date of today if it is equal to or less than daysDay (day item inside of daysData)
Here is the code for my array:
// Here I initalize the array with useState
const [daysData, setDaysData] = useState([]);
// Here is the port I'm fetching my array from.
useEffect(() => {
fetch('http://localhost:5001/chocolates')
.then((resp) => resp.json())
.then((data) => setDaysData(data));
}, []);
And here is the date code:
// Initiate new Date
const current = new Date();
// Retrieve current day of the month
const date = current.getDate();
I can't seem to get the effect I want. I basically only want to see if the day has passed or if it is today then I want it to post to '/open/chocolate'.

That's probably because the value of daysData is set asynchronously, yet the useEffect block that depends on it does not list it as a dependency. Therefore you are invoking logic, which requires daysData to be populated asynchronously, when the component is loaded at runtime. So daysData will be empty.
A solution is to simply add daysData in the dependency array, so that you will only execute whatever logic that is in there once the array is successfully populated.
On the other hand, you are comparing a number against an array: which will give an unexpected result. If you want any of the day to meet date + 1, use daysDay.some(d => date + 1 >= d). If you want all of the days to meet date + 1, use daysDate.every(d => date + 1 >= d).
useEffect(async () => {
const daysDay = daysData.map((day) => day.day);
// This needs to be fixed, see comment for options
if (daysDay.some(d => date + 1 > d)) {
// Url where to post
await axios.post(`http://localhost:5001/open/chocolate`, {
day: date,
});
}
setOpenCalendarBox('');
}, [daysData]);

How to filter last day in an array?

I have an array of objects like this:
[
{
created: "2019-08-14T13:24:36Z",
email: "test1#gmail.com"
},
{
created: "2019-08-15T13:24:36Z",
email: "test2#gmail.com"
},
{
created: "2019-08-16T13:24:36Z",
email: "test1#gmail.com"
},
{
created: "2019-08-22T13:24:36Z",
email: "test4#gmail.com"
},
{
created: "2019-08-22T15:29:66Z",
email: "test1#gmail.com"
}
]
The array is sorted by created. I want to filter those records which are on the last day, irrespective of the time on that day. I added the timestamp using moment.js. Something on these lines:
router.get('/GetLastDayRecords', (req, res) => {
res.json(allRecords.filter(record => record.created.max()));
});

Split the task: first get the maximum date which you'll find at the end of the sorted array (just getting the "YYYY-MM-DD" part of it is enough) and then launch the filter:
let max = allRecords.length ? allRecords[allRecords.length-1].created.slice(0,10) : "";
res.json(allRecords.filter(({created}) => created >= max));

First you need to figure out which day is the last day. If you can assume the records are already sorted, then this is pretty simple:
// Assuming your records are stored in the variable "records"
var lastDay = records[records.length - 1].created;
Now here's where your specific answer may differ based on how you want to handle time zones. Suppose one event happened at 11 PM EST (3 AM GMT) and another event happened at 1 AM EST (5 AM GMT). Are these the same day? In Europe they are, but in America they aren't!
What you need to do is create some cipher from the date+time listed to a "day". This way you can compare two "days" to see if they're the same:
lastDay = new Date(lastDay);
// Setting hours, minutes, and seconds to 0 will give you just the "day" without the time, but by default will use the system timezone
lastDay.setHours(0);
lastDay.setMinutes(0);
lastDay.setSeconds(0);
Once you know which day was the last, it's a simple filter:
// Using a for loop
var results = []
for (var i = 0; i < records.length; i++)
{
if (records[i].created > lastDay) {
results.push(records[i]);
}
}
// Using .filter
var results = records.filter(x => x.created > lastDay);
Alternatively, since we know it's already sorted, we can do it a bit more efficiently by binary searching for the first record on the last day, then grabbing all records after that:
var test = records.length / 2;
var step = records.length / 4;
var found = false;
while (!found) {
if (records[test].created < lastDay) {
test += step;
step /= 2;
}
else if (records[test].created > lastDay) {
if (step == 1) {
// We found the exact cut-off
found = true;
}
else {
test -= step;
step /= 2;
}
}
}
var results = records.slice(test);
Because you're only interested in the "last" day, the logic is a bit simpler. If you wanted the "third" day, you would need to check if created was after the start of the third day and before the end of the third day. We can just check if it's after the start of the last day.

I would create a function to turn your created properties into data be easily compared.
I would also avoid trying to do the entire filter operation in one or two lines as it will difficult to read by other developers.
const dateToInt = date => parseInt( date.split('T').shift().replace(/-/g, '') );
The above will:
Split your created property into an array of date and time.
Select the first element, which happens to be the date.
Remove the dashes in the date.
Coerce the value into a number.
With this you can find the maximum value and filter based on that value.
const nums = foo.map( ({ created }) => dateToInt(created) )
First get a list of numbers from the dataset.
const max = Math.max( ...nums )
Get the biggest number in the list.
const lastDays = foo.filter( ({ created }) => dateToInt(created) === max )
With all that setup, getting the max date is very easy and readable.
Of course, since the list is already sorted. You could have just done this as well.
const last = foo[foo.length -1].created;
const lastDays = foo.filter( ({ created }) => created === last )

I wrote a solution using reduce and filter:
const lastDay = arr.reduce((acc, el) => {
const date = el.created.substr(0,10);
const oldDate = new Date(acc);
const nextDate = new Date(date);
if(oldDate.getTime() > nextDate.getTime()) {
return oldDate;
} else {
return nextDate;
}
}, '1900-01-01');
const lastDayArr = arr.filter(el => {
const date = el.created.substr(0,10);
const oldDate = new Date(lastDay);
const nextDate = new Date(date);
return (oldDate.getTime() === nextDate.getTime());
});
First, you find the most recent date, reducing the original array by comparing which date is the most recent, for this you drop the part of the created string that specifies the hours/minutes/seconds.
You can use a very distant in time date as initial value, or you can set it to null and add another validation in your callback function.
As a second step, you use filter, using the same technique of dropping the hours/minutes/seconds of the created string.
The end result is an array of the elements with the most recent date in your original array.
If you can assume the array is sorted, you can skip the reduce method and just do:
const lastDay = arr[arr.length - 1].created.substr(0,10);

This should work:
allRecords.filter( record => {
let last_date = allRecords[ allRecords.length - 1].created
return last_date.slice(0, 10) === record.created.slice(0, 10)
})
Basically, you are getting the last element from your array and slicing its created value down to its date. Then you are slicing your current record's created value down to its date and comparing if they are the same.

Assuming that the array is already ASC ordered:
const onLastDay = values.filter( v => {
const last = moment(values[ values.length - 1 ].created)
const differenceInDays = last.diff(moment(v.created), 'days')
return differenceInDays < 1
})
console.log(onLastDay)
NOTE: If you try with the reported array you get an error due the fact that the last date is not valid! There are 66 seconds!

Checking for part of a key value pair

I am currently trying to develop an app that displays the parking tickets in NYC. The API I am using is https://data.cityofnewyork.us/resource/ati4-9cgt.json. I am trying to create a graph in which it shows how many tickets were distributed per month. There is a column called "issue_date", and it has year, month, followed by a bunch of numbers I am unsure of. Is it possible to only check the year and month part, instead of the whole value? For example, if I only want to see if the ticket was issued in January, I would check for 2017-01, but how would I make it so that the rest of the value doesn't get accounted and break the code? Thank you!
I forgot to include that I am a first year in college. I have limited knowledge on programming, sorry for the inconvenience.

You can just grab the first 7 characters from the date.
Here is some code to count the number of entries per month and put that in an array:
fetch("https://data.cityofnewyork.us/resource/ati4-9cgt.json")
.then(resp => resp.json()).then(data => {
const byMonth = Object.entries(data.reduce( (acc, row) => {
const month = row.issue_date.slice(0,7); // <--- just taking YYYY-MM
acc[month] = acc[month] || 0;
acc[month]++; // <--- counting
return acc;
}, {})).sort((a, b) => a[0].localeCompare(b[0])); // <--- sorting months
console.log(byMonth); // <--- output [[month, count], [month, count], ...]
});

Match issuedate with regexp, e.g. /^2017-01/
So if you have this whole array, you could:onlyOnJanuary2017 = wholeArray.filter(object => object.issue_date.match(/^2017-01/)); as here: https://jsfiddle.net/twpq6nvd/
Additionaly, if you want to bucket themm try this
var result = arr.reduce((accumulator, item) => {
const date = new Date(item.issue_date)
var key = `${date.getFullYear()}-${date.getMonth()}`
accumulator[key] = accumulator[key] || [];
accumulator[key].push(item);
return accumulator;
}, {})
https://jsfiddle.net/d3qa96bg/1/

Firebase / MomentJS Inconsistent Values

I have this:
init(userId: string = this.authProvider.currentUserId) {
this._subscription.add(this.db.list(`meetings/${userId}`)
.subscribe((meetings: any[]) => {
this._meetings = meetings.map((meeting) => {
meeting.Date = meeting.Date;
meeting.Ends = moment.tz(meeting.Ends, 'HH:mm', meeting.Location.TimeZone).local().format('HH:mm');
meeting.Starts = moment.tz(meeting.Starts, 'HH:mm', meeting.Location.TimeZone).local().format('HH:mm');
return Meeting.Parse(meeting);
});
}));
}
On any change from firebase, meeting.Starts, meeting.Ends values are preserved after being parsed by moment.tz.
So assuming on first subscription meeting.Starts is 11:00. After doing meeting.Starts = moment.tz... which will result in say 13:00 then next time anything happens on firebase end and the subscription is triggered, the value of Starts becomes 15:00 assuming the timezone adds 2 hours.
(The value in firebase is correct...) What's happening?

You appear to be using AngularFire2.
The problem is that you are mutating the items in the list. When changes occur, AngularFire2 updates only the items that are affected by the change. However, you are mutating all of the items - so moment.tz will be re-applied to any items that have not changed.
One solution would be to not mutate the items:
init(userId: string = this.authProvider.currentUserId) {
this._subscription.add(this.db.list(`meetings/${userId}`)
.subscribe((meetings: any[]) => {
this._meetings = meetings.map(meeting => Meeting.Parse({
...meeting,
Ends: moment.tz(meeting.Ends, 'HH:mm', meeting.Location.TimeZone).local().format('HH:mm'),
Starts: moment.tz(meeting.Starts, 'HH:mm', meeting.Location.TimeZone).local().format('HH:mm');
}));
});
}
Or, without the spread properties syntax:
init(userId: string = this.authProvider.currentUserId) {
this._subscription.add(this.db.list(`meetings/${userId}`)
.subscribe((meetings: any[]) => {
this._meetings = meetings.map(meeting => Meeting.Parse(
Object.assign({}, meeting, {
Ends: moment.tz(meeting.Ends, 'HH:mm', meeting.Location.TimeZone).local().format('HH:mm'),
Starts: moment.tz(meeting.Starts, 'HH:mm', meeting.Location.TimeZone).local().format('HH:mm');
})
));
});
}