when i got a JSON file called "test.json" which looks like this:
[{
"name":"abc",
"parent":"null",
"children":[],
}
]
That means with the outer brackets [] wrapping the whole data, it is not possible to use it in d3.js with the hierarchy function:
d3.json("test.json", function(a) {
var hierarchy = d3.hierarchy(a),
links = hierarchy.links()
nodes = hierarchy.descendants();
Now, when i leave the brackets away, which means that "test.json" looks like this, it is possible to use the file:
{
"name":"abc",
"parent":"null",
"children":[],
}
Now, my question is: Is this a specific problem of d3.js in general, maybe with the combination of the hierarchy function or it is always not working, when wrap the whole file with brackets []?
The outer brackets signify an array. To get the object / map inside them, index it out:
a[0]
So if a is:
[ {
"name": "abc",
"parent": "null",
"children": []
}
]
Then a[0] is just
{
"name": "abc",
"parent": "null",
"children": []
}
Related
const aboutMe = [{
"name": "frank",
"about": [{
"mood": "happy",
"dinner": [{
"first": "desert",
"last": "noodles"
}]
},
{
"mood": "happy",
"dinner": [{
"first": "desert",
"last": "noodles"
}]
},
{
"mood": "happy",
"dinner": []
}
]
}]
const AllBreak = aboutMe.about.map((dinner) => ((dinner.first, dinner.last)));
const expectedOutput =["first": "desert", "last": "noodles", "first": "desert", "last": "noodles"]
console.log(aboutMe, AllBreak, expectedOutput)
so am trying to filter through a nested array learning from a tutorial I don't know why it returns cannot read property of map why is that pretty sure i filtered correctly according to the tutorial
Firstly, aboutMe is an array with an object that has an about property in it. So, if you want to access this property, you need to first access the first element of the array and then access the about property in it.
Secondly, (dinner.first, dinner.second) doesn't actually make any sense here.
Because when you have multiple expressions separated by commas in a bracket, each of those expressions get evaluated but only the last one is returned. So, here returning (dinner.first, dinner.second) is equivalent to returning dinner.second.
So, if you only want dinner.second then just return that or put them in an array (or object) and return that.
Also, since in your example it seems that it is not guaranteed that the dinner array would always have an object inside it, it is best to use Optional Chaining here.
Please have look at the solution below:
const
aboutMe = [{name:"frank",about:[{mood:"happy",dinner:[{first:"desert",last:"noodles"}]},{mood:"happy",dinner:[{first:"desert",last:"noodles"}]},{mood:"happy",dinner:[]}]}],
res = aboutMe[0].about.map(({dinner}) => [dinner?.[0]?.first, dinner?.[0]?.last])
console.log(res);
aboutMe is an array, if you want to get the property of the first element, you can use indexing [0]
const AllBreak = aboutMe[0].about.map(() => ...);
I am trying to delete a 2 levels deep nested Reference in Firestore. My Schema looks like this:
In Code it looks like this:
{
"folder": "bla",
"title": "myTitle",
"children": [
{
"ref": "firstReference"
},
{
"ref": "secondReference"
},
{
"title": "Subcollection Title",
"children": [
{
"ref": "thirdReference"
},
{
"ref": "forthReference"
}
]
}
]
}
Now i am searching a way to remove the third or forth Reference from the second children array.
To remove an item from the first children array is use this code:
docRef.update({children: firebase.firestore.FieldValue.arrayRemove(folder.children[index])
But this solution works only for the top level ;(
Does somebody know how to remove deeper Nested elements?
I tried:
docRef.update({[`children[${index}].children`]: firebase.firestore.FieldValue.arrayRemove(
folder.children[index].children[secondIndex])});
But it throws an Error (Paths must not contain '~', '*', '/', '[', or ']')
Thanks for your help ;)
Firestore does not support modifying array items by index. FieldValue.arrayRemove only works if you pass the exact contents of the data to remove from an array field. If you only know the index, then what you'll have to do is read the document, modify the array in memory, then write the new document contents back.
I am trying to use underscoreJs to manipulate a JavaScript object and having problems doing so.
Here is my example
var data = {
"label": "SomeName",
"parent": [{
"id": "parentId",
"resources": [{
"name": "ID1NAME",
"calls": [
"user_get", "user2_post", "user3_delete"
]
}, {
"name": "ID2",
"calls": [
"employee1_get", "employee2_delete", "employee3_update"
]
}]
}]
};
var res = _(data).chain().
pluck('parent').
flatten().
findWhere(function(item){
item === "user_get"
}).
value();
console.log(res);
Using an element which is a part of data.parent.calls[] (example : "user_get") I would like to extract its parent object, i.e. data.parent[0].
I tried above but always get undefined. I appreciate any help on this.
One of the problems you're having is your use of _.pluck. If you execute _.pluck over an object, it'll go over the keys of the object trying to retrieve the property you specified as the second argument (in this case, 'parent'). 'label' is a string and 'parent' is an array so thus the array that you get as a result is [undefined, undefined]. The rest will then go wrong.
One solution could be as follows:
function findCallIndexInParent(call, parent) {
return _.chain(parent)
.pluck('resources')
.flatten()
.findIndex(function (obj) {
return _.contains(obj.calls, call);
})
.value();
}
function findCall(call, data) {
var parent = data.parent;
return parent[findCallIndexInParent(call, parent)];
}
console.log(findCall('user_get', data));
findCall is just a convenient method that will pass the parent property of data to findCallIndexInParent (that will retrieve the index where call is) and return the desired object with the parent array.
Lodash (a fork of underscore) provides a method to get the property of an object that would have come really handy in here (sadly, underscore doesn't have it).
The explanation of findCallIndexInParent is as follows:
Chain the parent list
pluck the resources array
As pluck maps, it returns a list of lists so a flatten is needed.
Find the index of the element which calls contains call
Return the value (the index) of the object that contains call within parent.
Here's the fiddle. Hope it helps.
This would seem to do the trick.
function findByCall(data, call) {
return _.find(data.parent, function(parent) { //From data.parent list, find an item that
return _.some(parent.resources, function(resource) {//has such parent.resource that it
return _.includes(resource.calls, call); //includes the searched resource.calls item
});
});
}
//Test
var data = {
"label": "SomeName",
"parent": [{
"id": "parentId",
"resources": [{
"name": "ID1NAME",
"calls": [
"user_get", "user2_post", "user3_delete"
]
}, {
"name": "ID2",
"calls": [
"employee1_get", "employee2_delete", "employee3_update"
]
}]
}]
};
console.log(findByCall(data, 'user_get'));
<script src="https://cdnjs.cloudflare.com/ajax/libs/underscore.js/1.8.3/underscore.js"></script>
If I understand correctly, you want to get the index of the element in the parent array which has any resource with the specified call.
data = {
"label": "SomeName",
"parent": [{
"id": "parentId",
"resources": [{
"name": "ID1NAME",
"calls": [
"user_get", "user2_post", "user3_delete"
]
}, {
"name": "ID2",
"calls": [
"employee1_get", "employee2_delete", "employee3_update"
]
}]
}]
}
// find the index of a parent
const index = _.findIndex(data.parent, parent =>
// that has any (some) resources
_.some(parent.resources, resource =>
// that contains 'user_get' call in its calls list
_.contains(resource.calls, 'user_get')
)
)
console.log(index) // 0
<script src="https://cdnjs.cloudflare.com/ajax/libs/underscore.js/1.8.3/underscore-min.js"></script>
If you want to find the actual parent object, use find instead of findIndex
If you want to find all parent objects matching this call, use filter instead of findIndex
I'm hitting an api built using CakePHP. Cake returns its objects like this:
[
{
"Note": {
"id": "1",
"clas": "test",
"obj_id": null,
"note": "test"
}
},
{
"Note": {
"id": "2",
"clas": "another",
"obj_id": null,
"note": "another"
}
}
]
What I want to do is take that result and basically get rid of the keys. Something like this:
[
{
"id": "1",
"clas": "test",
"obj_id": null,
"note": "test"
},
{
"id": "2",
"clas": "another",
"obj_id": null,
"note": "another"
}
]
I'm basically just trying to make it easier to reference this in Angular. I need to do this on the client side. Any ideas?
You could refactor it like so:
var json = '[{"Note":{"id":"1","clas":"test","obj_id":null,"note":"test"}},{"Note":{"id":"2","clas":"another","obj_id":null,"note":"another"}}]';
var obj = JSON.parse(json);
var arr = [];
for (i = 0; i < obj.length; i++)
{
arr.push(obj[i].Note);
}
Working example here
(Note also that if your key value 'Note' isn't always the same, this will change dramatically. It's likely that 'Note' isn't going to be the same in each instance either; that would generate an improperly keyed object. Alternatively, if you always need the first object in the array, you could use obj[i][0] instead).
(More note if you're using cakephp, this would be much easier done using Hash::, but if you need to do it client side, this is the solution).
This is my sample JSON file , which im trying to parse and read the values ....
C = {{
"Travel": {
"ServiceProvider": {
"Name": "SRS",
"Rating": "3 stars",
"Rates": "Nominal",
"Features": {
"OnlineBooking": "Yes",
"SMS_Ticket": "No"
},
"UserDetails": {
"Name": "Jack",
"Age": "33",
"Gender": "Male"
}
},
"BusProvider": {
"Name": "SRS",
"Rating": "3 stars",
"Rates": "Nominal",
"Features": {
"OnlineBooking": "Yes",
"SMS_Ticket": "No"
},
"UserDetails": {
"Name": "Jack",
"Age": "33",
"Gender": "Male"
}
}
}
}
I'm pretty new to JS , and i need to access the nested elements in a generic fashion.
Im not able to extract the details properly. Im getting stuck accessing nested the child elements.
The problem for me is that i wont always know the names of the "key's' to acess them , the JSON will be dynamic , hence i need a generic mechanism to acess the nested child elements. The Nesting can go upto 3 -4 levels.
what notation do we use to access the key / value pairs when the nesting is deep.
Any Help would be appreciated.
ater desirializing your object you can do this
var resultJSON = '{"name":"ricardo","age":"23"}';
var result = $.parseJSON(resultJSON);
$.each(result, function(k, v) {
//display the key
alert(k + ' is the key)
}
you can do it using recursively offcourse like this - Link Here
the way is the same just adapt to your example
For dynamic access you can use brackets notation i.e. var json = {nonKnown: 1}; now you can access it like that:
var unknowPropertyName = "nonKnown";
var value = json[unknownPropertyName];
But if you can not even define dynamically name of the property, then you should use
for(variableName in json){
if(json.hasOwnProperty(variableName)){
console.log(variableName);
}
}
You should get the basic idea from this. Good luck