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Comparing two arrays of objects and removing when two match

I was wondering if anyone could help me. I am using React and I have two arrays of objects:
one for all possible booking times
the other for existing bookings.
I am struggling to find a way of successfully looping over the allSlots array and removing any that have a matching time inside the existingBookings array.
In the example below, there are existing bookings at 10:00am, 10:40am, 11:00am and 11:20am.
The expected output would only leave 10:20am and 11:40am from the original array.
const allSlots = [
{
date: "28 Sept 22",
time: "10:00am"
},
{
date: "28 Sept 22",
time: "10:20am"
},
{
date: "28 Sept 22",
time: "10:40am"
},
{
date: "28 Sept 22",
time: "11:00am"
},
{
date: "28 Sept 22",
time: "11:20am"
},
{
date: "28 Sept 22",
time: "11:40am"
}
];
const existingBookings = [
{
time: "10:00am",
propertyID: "XQPvl7MmLVNtxHdSRfDq",
userID: "Bq4b3uz129aE2D5TCbaOiLQJrvC2",
date: "28 Sept 22"
},
{
time: "11:00am",
propertyID: "XQPvl7MmLVNtxHdSRfDq",
userID: "Ko2LdnQAdaE2OiLQJrvC2D5TCbA",
date: "28 Sept 22"
},
{
time: "10:40am",
propertyID: "XQPvl7MmLVNtxHdSRfDq",
userID: "Ko2LdnQAdaE2OiLQJrvC2D5TCbA",
date: "28 Sept 22"
},
{
time: "11:20am",
propertyID: "XQPvl7MmLVNtxHdSRfDq",
userID: "iLQJrKo2LdCbnQAdaE2OvC2D5TA",
date: "28 Sept 22"
}
];
I originally filtered the existingBookings data down to remove any that did not match the selected date with:
const existingBookings = allBookings.filter(
(booking) => booking.date === selectedDate
);
However, I am struggling to manipulate things further. I really appreciate any insight and help you may be able to give.

It is as simple as doing
freeSlots=allSlots.filter(s=>
existingBookings.every(e=>e.time!=s.time||e.date!=s.date)
)
Here is a working (plain) JavaScript snippet:
const allSlots = [
{
date: "28 Sept 22",
time: "10:00am"
},
{
date: "28 Sept 22",
time: "10:20am"
},
{
date: "28 Sept 22",
time: "10:40am"
},
{
date: "28 Sept 22",
time: "11:00am"
},
{
date: "28 Sept 22",
time: "11:20am"
},
{
date: "28 Sept 22",
time: "11:40am"
}
];
const existingBookings = [
{
time: "10:00am",
propertyID: "XQPvl7MmLVNtxHdSRfDq",
userID: "Bq4b3uz129aE2D5TCbaOiLQJrvC2",
date: "28 Sept 22"
},
{
time: "11:00am",
propertyID: "XQPvl7MmLVNtxHdSRfDq",
userID: "Ko2LdnQAdaE2OiLQJrvC2D5TCbA",
date: "28 Sept 22"
},
{
time: "10:40am",
propertyID: "XQPvl7MmLVNtxHdSRfDq",
userID: "Ko2LdnQAdaE2OiLQJrvC2D5TCbA",
date: "28 Sept 22"
},
{
time: "11:20am",
propertyID: "XQPvl7MmLVNtxHdSRfDq",
userID: "iLQJrKo2LdCbnQAdaE2OvC2D5TA",
date: "28 Sept 22"
}
];
const freeSlots=allSlots.filter(s=>
existingBookings.every(e=>e.time!=s.time||e.date!=s.date)
)
console.log(freeSlots);

You want to filter your allSlots array so that it only contains slots not present in existingBookings
const unusedSlots = allSlots.filter((slot) => {
// See if the slot is booked
const isBooked = existingBookings.some(
(booking) => booking.time == slot.time && booking.date == slot.date
)
// Only keep free slots
return !isBooked
});

This should work.
const newAllSlots = allSlots.filter((slot)=>{
const iSInExistingBookings = existingBookings.find(booking=>booking.time === slots.time && booking.date === slots.date)
return !iSInExistingBookings
})

Since you know what you already have booked with existingBookings, I would suggest looping through that first. Then you can recursively filter the allSlots array back into itself by checking if the date matches but the time does not. Once completed, the allSlots array should only have the date and times that haven't been booked.
existingBookings.forEach(booking => {
allSlots = allSlots.filter(slot => {
return booking.date === slot.date && booking.time !== slot.time;
});
});
Edit: You will have to scope allSlots with let instead of const for this to work. You could also assign allSlots to another variable if you want to keep allSlots in tact:
let slots = allSlots;
existingBookings.forEach(booking => {
slots = slots.filter(slot => {
return booking.date === slot.date && booking.time !== slot.time;
});
});

map on the lower level key of a nested object

I had posted this question earlier but someone deleted with How can I access and process nested objects, arrays or JSON?
as possible answer. This is not helping me since a) The key 'date' is spread across several names, b)The objects comprises on arrays & objects & c) The depth at which the key 'date' is present can change.
Hence posting the question again.
I have a JS object as below
const bb = {
Harry: {
details: [
{
cat: "Life",
values: [
{
date: "2021-08-02",
level: 77.6,
},
{
date: "2021-08-03",
level: 79.1,
},
],
},
],
},
Barry: {
details: [
{
cat: "Logic",
values: [
{
date: "2021-08-02",
level: 77.6,
},
{
date: "2021-08-03",
level: 79.1,
},
],
},
],
},
};
I also have a variable defined for parsing the dates const dateParse = d3.timeParse("%Y-%m-%d")
I want to parse all the dates in the object. Since the 'date' is few levels below in the object, I am not able to figure this out. How do I go about it?
The expected output is
const bb = {
Harry: {
details: [
{
cat: "Life",
values: [
{
date: Mon Aug 02 2021 00:00:00 GMT+0530 (India Standard Time),
level: 77.6,
},
{
date: Tue Aug 03 2021 00:00:00 GMT+0530 (India Standard Time),
level: 79.1,
},
],
},
],
},
Barry: {
details: [
{
cat: "Logic",
values: [
{
date: Mon Aug 02 2021 00:00:00 GMT+0530 (India Standard Time),
level: 77.6,
},
{
date: Tue Aug 03 2021 00:00:00 GMT+0530 (India Standard Time),
level: 79.1,
},
],
},
],
},
};

You just have to loop through the objects, select the date node and execute
(new Date(datestring)).toString()
This will generate the date as specified in your output.
const bb = { Harry: { details: [{cat: "Life",values: [{date: "2021-08-02",level: 77.6},{date: "2021-08-03",level: 79.1}]}]},Barry: {details: [{cat: "Logic",values: [{date: "2021-08-02",level: 77.6},{date: "2021-08-03",level: 79.1}]}]}};
Object.values(bb).forEach((value) => {
value.details.forEach((detail) => {
detail.values.forEach((value) => {
value.date = (new Date(value.date)).toString();
})
})
});
console.log(bb);

If you want to parse all the nested date keys, you can do it recursively using the below functions
const bb = { Harry: { details: [{cat: "Life",values: [{date: "2021-08-02",level: 77.6},{date: "2021-08-03",level: 79.1}]}]},Barry: {details: [{cat: "Logic",values: [{date: "2021-08-02",level: 77.6},{date: "2021-08-03",level: 79.1}]}]}};
function traverseArray(inputArray) {
for (const arrayValue of inputArray) {
traverseObject(arrayValue);
}
}
function traverseObject(inputObject) {
for (const key in inputObject) {
const value = inputObject[key];
const valueType = typeof(value);
if (valueType == "object") {
traverseObject(value);
} else if (valueType == "array") {
traverseArray(value);
} else if (key == "date") { // since I want to parse only date keys
inputObject[key] = 'd3.timeParse("%Y-%m-%d") - Parse date here';
}
}
}
traverseObject(bb);
console.log(bb);

Get common data from multiple arrays of object that containing a unique id and nested array using javascript es6

I am trying to find the common data from multiple arrays of object that contains a unique id (mongoose object id) and an array of string.
for example:
array1 = [{
_id: "60f027f98b55eb2df1f36c04",
date: "2021-07-15T12:18:12.223Z",
time: "30",
hours: ["8:00 AM", "8:30 AM"]
}]
array2 = [{
_id: "60f027f98b55eb2df1f36c05",
date: "2021-07-15T12:18:12.223Z",
time: "60",
hours: ["7:30 AM", "8:30 AM", "9:30AM"]
}]
array3 = [{
_id: "60f027f98b55eb2df1f36c06",
date: "2021-07-16T12:12:12.223Z",
time: "30",
hours: ["7:00 AM", "8:30 AM"]
}]
The output should have maximum common values in the arrays for maximum common dates and that date should have maximum common hour.
So the sample output should look something like this.
common_data = {
date: "2021-07-15T12:18:12.223Z",
time: "30",
hours: "8:30AM"
}
I looked up at other answers and tried something like this:
merged all the arrays and
let result = merged_slots_array.shift().filter(function(v) {
return merged_slots_array.every(function(a) {
const matchDate = a.date === v.date;
const getMatchTime = a.hours.shift().filter(function(x) {
return v.hours.every(function(t) {
return x.indexOf(t) !== -1;
})
});
return matchDate && getMatchTime
});
});
but getting error merged_slots_array.shift(...).filter is not a function

After concatenating the arrays, finding the max common hour can be done through a filter that only keeps duplicates, then gets sorted. Once we have that, we can query each array to make sure it contains the max hour, then extract the max date and time. My output was slightly different than yours because i filtered for the max time, hour and date
array1 = [{
_id: "60f027f98b55eb2df1f36c04",
date: "2021-07-15T12:18:12.223Z",
time: "30",
hours: ["8:00 AM", "8:30 AM"]
}]
array2 = [{
_id: "60f027f98b55eb2df1f36c05",
date: "2021-07-15T12:18:12.223Z",
time: "60",
hours: ["7:30 AM", "8:30 AM", "9:30AM"]
}]
array3 = [{
_id: "60f027f98b55eb2df1f36c06",
date: "2021-07-16T12:12:12.223Z",
time: "30",
hours: ["7:00 AM", "8:30 AM"]
}]
const getCommon = (arrays) => {
let group = [].concat.apply([], [...arrays])
let hour = group.map(e=>e.hours).flat().filter((e,i,a) => a.indexOf(e) !== i).sort((a,b) => a.localeCompare(b))[0]
let common = group.filter(e=>e.hours.includes(hour))
let time = Math.max(...common.map(e => +e.time))
let date = common.map(e => e.date).sort((a,b) => new Date(b) - new Date(a))[0];
return {date: date, time: time, hours: [hour]}
}
let arg = []
arg.push(array1)
arg.push(array2)
arg.push(array3)
console.log(getCommon(arg))
TS Playground

Can't loop over grouped array in JS

Unfortunately I have again problems with my grouped messages. I have already received a lot of help from you, so I feel a bit embarrassed to ask again - but I'm not getting ahead with this.
My first goal was to group messages by their created_date. Thanks to your help this works very well now. Now I have tried to output the grouped messages, but it does not work. I slowly don't understand the whole thing anymore...
I want to output the group key (date) first and then every single message in each group. This is what I’ve tried:
jQuery(document).ready(function ($) {
let messages = [{
sender_id: "0",
message: "Test",
created_at: "Thu Mar 12 2020 17:26:23 GMT+0100 (Mitteleuropäische Normalzeit)"
}, {
sender_id: "0",
message: "Hallo",
created_at: "Thu Mar 12 2020 17:26:23 GMT+0100 (Mitteleuropäische Normalzeit)"
}];
let groupedMessages = [];
$(messages).each(function (index, message) {
let createdAtDate = new Date(message["created_at"]).toLocaleDateString(navigator.language, {
day: "2-digit",
month: "2-digit",
year: "numeric"
});
if (typeof groupedMessages[createdAtDate] === "undefined") {
groupedMessages[createdAtDate] = [];
}
groupedMessages[createdAtDate].push(message);
});
console.log(groupedMessages);
if (groupedMessages && groupedMessages.length > 0) {
$(groupedMessages).each(function (index, messages) {
console.log(index); //Expected output: 12.03.2020
$(messages).each(function (index, message) {
console.log(message["sender_id"]);
console.log(message["message"]);
console.log(message["created_at"]);
})
});
}
});
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>

The issue is because of this line
let groupedMessages = []
You are setting groupedMessages as an array when it should be an object. array's don't have keys in JavaScript, which is why you get no output.
jQuery(document).ready(function ($) {
let messages = [{
sender_id: "0",
message: "Test",
created_at: "Thu Mar 12 2020 17:26:23 GMT+0100 (Mitteleuropäische Normalzeit)"
}, {
sender_id: "0",
message: "Hallo",
created_at: "Thu Mar 12 2020 17:26:23 GMT+0100 (Mitteleuropäische Normalzeit)"
}];
let groupedMessages = {};
$(messages).each(function (index, message) {
let createdAtDate = new Date(message["created_at"]).toLocaleDateString(navigator.language, {
day: "2-digit",
month: "2-digit",
year: "numeric"
});
if (typeof groupedMessages[createdAtDate] === "undefined") {
groupedMessages[createdAtDate] = [];
}
groupedMessages[createdAtDate].push(message);
});
console.log(groupedMessages);
if (groupedMessages && groupedMessages.length > 0) {
$(groupedMessages).each(function (index, messages) {
console.log(index); //Expected output: 12.03.2020
$(messages).each(function (index, message) {
console.log(message["sender_id"]);
console.log(message["message"]);
console.log(message["created_at"]);
})
});
}
});
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>

To solve your problem I would suggest you such things:
You can`t use string keys for arrays, use objects in case you want to have string keys
Do not use $().each... because it iterates over jQuery collections, instead use built in js functions of $.each to iterate over js object or array.
Check solution below
jQuery(document).ready(function ($) {
let messages = [{
sender_id: "0",
message: "Test",
created_at: "Thu Mar 12 2020 17:26:23 GMT+0100 (Mitteleuropäische Normalzeit)"
}, {
sender_id: "0",
message: "Hallo",
created_at: "Thu Mar 12 2020 17:26:23 GMT+0100 (Mitteleuropäische Normalzeit)"
}];
let groupedMessages = {};
messages.forEach(function (message, index) {
let createdAtDate = new Date(message["created_at"]).toLocaleDateString(navigator.language, {
day: "2-digit",
month: "2-digit",
year: "numeric"
});
if (typeof groupedMessages[createdAtDate] === "undefined") {
groupedMessages[createdAtDate] = [];
}
groupedMessages[createdAtDate].push(message);
});
console.log(groupedMessages);
if (Object.keys(groupedMessages).length)
{
Object.keys(groupedMessages).map(date => {
console.log(date); //Expected output: 12.03.2020
groupedMessages[date].map(message => {
console.log(message["sender_id"]);
console.log(message["message"]);
console.log(message["created_at"]);
})
});
}
});
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>

Combine objects of an array with the same date into one - JavaScript

I receive an array of posts through an API and want to merge the ones with the same "month" and "year" (day is not important), into one object. I looked up for answers but there are just too many foo-bar examples that confuses more than helping. I want to know the cleanest, most elegant way of handling such problems, without getting into call-back hell and nested blocks...
Here is the API response:
0:
{
date: {day: 27, month: 1, year: 2020}
id: 3
}
1:
{
date: {day: 28, month: 1, year: 2020}
id: 4
}
2:
{
date: {day: 31, month: 1, year: 2020}
id: 5
}
3:
{
date: {day: 1, month: 2, year: 2020}
id: 6
}
4:
{
date: {day: 2, month: 2, year: 2020}
id: 7
}
The expected outcome:
0:
result: {month: 1, year: 2020, id:[3,4,5]}
1:
result: {month: 2, year: 2020, id:[6,7]}

One approach would be to use the Array#reduce() method to transform the input array into a dictionary, where each value contains the accumulation of id's for that month and year. Once this dictionary has been built, you could then extract the values of that dictionary to an array via Object#values() to obtain the required output:
let input=[{date:{day:27,month:1,year:2020},id:3},{date:{day:28,month:1,year:2020},id:4},{date:{day:31,month:1,year:2020},id:5},{date:{day:1,month:2,year:2020},id:6},{date:{day:2,month:2,year:2020},id:7}];
/* Convert the dictionary that will be created by reduce to a value array */
var output = Object.values(input.reduce((dict, item) => {
const { date, id } = item;
/* The distinct key for this item based on month/year of date field */
const key = `${date.month}-${date.year}`;
/* Check if dictionary already has an object value for key. This short hand
will only insert a new object value for key, if one does not already exist
in the dictionary */
const value = dict[key] || { month : date.month, year : date.year, id : [] };
/* Add the item id to the dictionary entries id array */
value.id.push(id);
/* Update value object for key */
return { ...dict, [key] : value };
}, {}))
console.log(output);
The idea here is that the dictionary is built using Compound Keys, where the keys are derived from the month and year of the current array item.
When no value exists for the current key, a new value object is inserted to the dictionary for that key:
{ month : date.month, year : date.year, id : [] }
The id of the current array item is then added (accumulated) to the id sub array of the object for that key:
dict[key].id.push(id);
Hope that helps

Here is an alternate approach, if you are not a big fan of Array.reduce and Array.values and also, if you like to consider performance when running the response for a larger data set.
This approach avoids cloning object (or rather non-mutating object) with spread operator i.e {...<anyObject>} while iterating. which should be fine for minimal set of data but but definitely not when you deal with huge volume.
const response = [{
date: { day: 27, month: 1, year: 2020 },
id: 3
}, {
date: { day: 28, month: 1, year: 2020 },
id: 4
}, {
date: { day: 31, month: 1, year: 2020 },
id: 5
},{
date: { day: 1, month: 2, year: 2020 },
id: 6
},{
date: { day: 2, month: 2, year: 2020 },
id: 7
}];
function groupByMonthYear(response) {
// output
const groupedData = []
// Using map for lookup to avoid iterating again on the grouped data
const referenceMap = new Map();
// destructing month, year and id from the response
for (const { date: { month, year }, id } of response) {
const groupKey = `${month}${year}`
// check if the month and year reference is already seen using the groupKey MMYYYY
if (referenceMap.has(groupKey)) {
referenceMap.get(groupKey).id.push(id);
// early return
continue;
}
// simply add a new entry if it doesn't exist
const data = {
month,
year,
id: [id]
};
groupedData.push(data);
referenceMap.set(groupKey, data)
}
return groupedData;
}
// Invoke and Print the result
console.log(groupByMonthYear(response));