Pushing object to Array makes parameter empty - javascript

I'm trying to solve problem of merging two arrays of objects, so I wrote a pretty simple function
function mergeShowtimes(movies) {
var existing_halls = [];
return movies.reduce(function(acc, movie) {
var movies_with_hallid,
movies_seats;
if (existing_halls.indexOf(movie.hallId) === -1) {
movies_with_hallid = _.filter(movies, function(filter_movie) {
return movie.hallId === filter_movie.hallId;
});
movies_seats = _.map(movies_with_hallid, 'seats');
movie.seats = _.union.apply(this, movies_seats);
acc.push(movie);
existing_halls.push(movie.hallId);
}
return acc;
}, []);
}
problem is, whenever I check the value of movie and movie.seats, field 'seats' in movie is empty, but movie.seats is not, for some reason
If I'll remove acc.push(movie); everything will start working as planned
What am I doing wrong?
Thanks for any feedback!

Related

Value is not changing in real time -- VueJS

I am using a JS class, I have following code:
class Field {
public Value = null;
public Items = [];
public UniqueKey = null;
public getItems() {
let items = [...this.Items];
items = items.filter((item) => {
if (item.VisibleIf) {
const matched = item.VisibleIf.match(/\$\[input:(.*?)\]/g);
if (matched?.length) {
const srv = Service.getInstance();
for (let match of matched) {
match = match.slice(8, -1);
if (srv.Fields?.length) {
let found = srv.Fields.find((x) => x.UniqueKey === match);
if (found) {
item.VisibleIf = item.VisibleIf.replace(
`$[input:${match}]`,
found.Value ?? ''
);
return JSON.parse('' + eval(item.VisibleIf));
}
}
}
}
}
return true;
});
return items;
}
public getInputTitle() {
let title = this.Title;
const matched = title.match(/\$\[input:(.*?)\]/g);
if (matched?.length && title) {
const srv = Service.getInstance();
for (let match of matched) {
match = match.slice(8, -1);
if (srv.Fields?.length) {
let found = srv.Fields.find((x) => x.UniqueKey === match);
if (found) {
title = title.replace(`$[input:${match}]`, found.Value ?? '');
}
}
}
}
return title;
}
}
Now I have a Vue component:
<div v-for="Field in Fields" :key="Field.UniqueKey">
<v-select
v-if="Field.Type == 'Select'"
:label="Field.getInputTitle()"
v-model="Field.Value"
:items="Field.getItems()"
item-text="Value"
item-value="Id"
/>
<v-input
v-else-if="Field.Type == 'Input'"
v-model="Field.Value"
:label="Field.getInputTitle()"
/>
</div>
// JS
const srv = Service.getInstance();
Fields = srv.getFields(); // <- API call will be there.
So basically, data comes from an API, having Title as Input $[input:uniqueKey], in a component I am looping over the data and generating the fields. See getInputTitle function in Field class, it works very well. All the fields which are dependent on the $[input:uniqueKey] are changing when I start typing into that field on which other fields are dependent.
Now I have pretty much same concept in the getItems function, so basically, what I want to do is whenever I type into a field and that field exists in the VisibleIf on the Items, the VisibleIf will be like '$[input:uniqueKey] < 1', or any other valid JavaScript expression which can be solved by eval function. But the getItems function is called only 1st time when page gets loaded, on the other hand the getInputTitle function which is pretty much same, gets called every time when I type into the field.
I tried to explain at my best, I will provide any necessary information if needed.
Any solution will be appreciated. Thanks.
You are updating the Object itself in here:
item.VisibleIf = item.VisibleIf.replace( `$[input:${match}]`, found.Value ?? '' );
Even though you tried to copy the array, but you have done shallow copy of the object in here: let items = [...this.Config.Items];
I suggest the following solution:
const visibleIf = item.VisibleIf.replace(
`$[input:${match}]`,
found.Value ?? ''
);
const val = '' + helpers.evalExp('' + visibleIf);
if (helpers.isJSON(val)) {
return JSON.parse(val);
}
Means instead of changing the VisibleIf object, just store it into the variable and just use that.
I hope that it will fix your issue. Let me know if it works.

push to Array in async function is not filtered

var listUsers= [];
for(let item of list){
var profile = await getOne(item.updatedBy);
var gettedUsers = await User.find(queryData).populate({path: "profiles"});
var users = gettedUsers.filter(user => user._id !== profile._id);
if(users) {
for(let gettedUser of users) {
if(!listUsers.includes(gettedUser.profile._id)){
listUsers.push(gettedUser.profile._id);
// do some stuff for the getted user
}
}
}
}
console.log(listUsers); // i get duplicated users
I had added this array list 'listUsers' to filter users and then for each one of them i can do some stuff, but the problem is that i get duplicated users.
Someone could help me ?
The solution is that I changed :
listUsers.includes(gettedUser.profile._id)
to :
var contains = (list, element) => list.some(elem =>{
return JSON.stringify(element) === JSON.stringify(elem);
});
I really don't know waht's the problem but i think I was comparing objects instead of strings. Anyway this solved it ;)

Knockout Check If Existing in observableArray before Push

I am new to Knockout and I have a little problem stopping me from completing my simple project.I have an observableArray called loanDeductions that I display in a table with foreach binding. I have another observableArray called loanDeductionsList which is also from the json data of my first observableArray, I used it in my drop down list which when a value is selected, it will push the selected data to my table. If it didn't make sense as I cannot really explain it clearly, this is my javascript file:
var deductionLine = function (deductionID, deductionName, amount) {
self = this;
self.deductionID = ko.observable(deductionID);
self.deductionName = ko.observable(deductionName);
self.amount = ko.observable(formatCurrency(amount));
};
function LoanDeductions(deductions) {
var self = this;
self.loanDeductions = ko.observableArray(ko.utils.arrayMap(deductions, function (deduction) {
return new deductionLine(deduction.deductionID, deduction.deductionName, deduction.amount)
}));
self.loanDeductionsList = ko.observableArray(ko.utils.arrayMap(deductions, function (deduction) {
return new deductionLine(deduction.deductionID, deduction.deductionName, deduction.amount)
}));
self.selectedDeduction = ko.observable();
self.selectedDeduction.subscribe(function (data) {
self.loanDeductions.push({
deductionID: data.deductionID,
deductionName: data.deductionName,
amount: data.amount,
});
});
}
Can you help me find a way to make my function selectedDeduction.subscribe() push the data ONLY when the item to be pushed is not existing in my loanDeductions observableArray.
Any help will be greatly appreciated. Thank you!
I am somewhat aware that the way I populate my dropdown list may o may not be the best way to do it, I am open to suggestion of a better way and rewrite my program.
just to share what I did I added this line in my selectedDeduction.subscribe():
self.selectedDeduction.subscribe(function (data) {
var match = ko.utils.arrayFirst(self.loanDeductions(), function(deduction) {
return deduction.deductionID() === data.deductionID();
});
if (match) {
alert(data.deductionName() + ' already exists!');
} else {
self.loanDeductions.push({
deductionID: data.deductionID,
deductionName: data.deductionName,
amount: data.amount,
});
}
});

Detect differences between two objects (JSON)

I've got a remote JSON file that contains the list of the last 100 users who logged into a service. This JSON is updated constantly and lists the users from the most recently logged in to the "least recently" logged in.
If the user who appears as number X logs back in, they get removed from their position X and put back at the very top of the JSON at position [0].
I retrieve the JSON every 5 minutes. What I'd like to do is detect the differences between the old object oldUsers and the new newUsers and store them in another object that would only contain the users who are present in newUsers but not in oldUsers. I have no real idea as to how to achieve this.
Here's the JSON structure:
[{
"id":"foo09",
"name":"John",
"age":28
}, {
"id":"bar171",
"name":"Bryan",
"age":36
},
...
]
Is there a rather straightforward way to do it? Thanks!
You need to write your own diff algorithm. Here is one I whipped up in JSBin:
I will need a utility function to merge two arrays (Underscore would help here).
function mergeArrays(val1, val2) {
var results = val1.splice(0);
val2.forEach(function(val) {
if (val1.indexOf(val) < 0) {
results.push(val);
}
});
return results;
}
Diff algorithm
function diff(val1, val2) {
var results = [];
var origKeys = Object.keys(val1);
var newKeys = Object.keys(val2);
mergeArrays(origKeys, newKeys)
.forEach(function(key) {
if (val1[key] === val2[key]) { return; }
var result = {
key: key,
orig: val1[key],
'new': val2[key]
};
if (val1[key] == null) {
result.type = 'add';
} else if (val2[key] == null) {
result.type = 'delete';
} else {
result.type = 'change';
}
results.push(result);
});
return results;
}

How do I remove all the extra fields that DOJO datastore adds to my fetched items?

When fetching an item from a DOJO datastore, DOJO adds a great deal of extra fields to it. It also changes the way the data is structure.
I know I could manually rebuild ever item to its initial form (this would require me to make updates to both JS code everytime i change my REST object), but there certainly has to be a better way.
Perhaps a store.detach( item ) or something of the sort?
The dojo.data API is being phased out, partly because of the extra fields. You could consider using the new dojo.store API. The store api does not add the extra fields.
I have written a function that does what you are looking to do. It follows. One thing to note, my function converts child objects to the { _reference: 'id' } notation. You may want different behavior.
Util._detachItem = function(item) {
var fnIncludeProperty = function(key) {
return key !== '_0'
&& key !== '_RI'
&& key !== '_RRM'
&& key !== '_S'
&& key !== '__type'
};
var store = item._S;
var fnCreateItemReference = function(itm) {
if (store.isItem(itm)) {
return { _reference: itm.id[0] };
}
return itm;
};
var fnProcessItem = function(itm) {
var newItm = {};
for(var k in itm) {
if(fnIncludeProperty(k)) {
if (dojo.isArray(itm[k])) {
// TODO this could be a problem with arrays with a single item
if (itm[k].length == 1) {
newItm[k] = fnCreateItemReference(itm[k][0]);
} else {
var valArr = [];
dojo.forEach(itm[k], function(arrItm) {
valArr.push(fnCreateItemReference(arrItm));
});
newItm[k] = valArr;
}
} else {
newItm[k] = fnCreateItemReference(itm[k]);
}
}
}
return newItm;
};
return fnProcessItem(item);
};
NOTE: this function is modified from what I originally wrote and I did not test the above code.

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