How to dynamically build object with nest objects and arrays - javascript

I want to dynamically build this object with the data below.
var object1 = {
machines: [
{
node: "01",
ram: "8",
disks: [ {sdasize: '20'}, {sdbsize: '200'} ],
mounts: [ {mount: "/var/lib", size: "10"} , {mount: "/home", size: "140"}]
},
{
node: "02",
ram: "8",
disks: [ {sdasize: '75'}, {sdbsize: '300'} ],
mounts: [ {mount: "/var/log", size: "20"} , {mount: "/var/www/html", size: "200"}]
}
]
};
I want to be able to add new machines and make changes to any value or add more mounts to the array that is nested. I have been looking at this for some time with no solution as of yet.

You can do this:
var object1 = {machines: []}
function addMachines(node,ram,disks,mounts){
object1.machines.push({node:node,ram:ram,disks:disks,mounts:mounts})
}
Since machines is a array we can use push() to insert objects inside that array.
Now you can use addMachines function in a loop or based on eventlisteners, and build the object1 via parameters in that function
Edit:
As commented below you can also add a function to build your other objects, like disks and mount.
buildDisk(sdasize,sdbsize)
{
return [{sdasize:sdasize},{sdbsize:sdbsize}]
}
Usage:
addMachines('01','8',buildDisk(20,50),'nice')
what object1 would look like
machines:[
{
node:'01',
ram:'8',
disks:[
{
sdasize:20,
sdbsize:50
},
mounts:'nice'
}];

Related

Destructuring object with inner array without all keys

I have an object like this:
const objBefore:
{
"id": "3pa99f64-5717-4562-b3fc-2c963f66afa1",
"number": "5000",
"enabled": true,
"classes": [
{
"id": "2fc87f64-5417-4562-b3fc-2c963f66afa4",
"name": "General"
},
{
"id": "7ffcada8-0215-4fb0-bea9-2266836d3b18",
"name": "Special"
},
{
"id": "6ee973f7-c77b-4738-b275-9a7299b9b82b",
"name": "Limited"
}
]
}
Using es6, I want to grab everything in the object except the name key of the inner classes array to pass it to an api.
So:
{
"id": "3pa99f64-5717-4562-b3fc-2c963f66afa1",
"number": "5000",
"enabled": true,
"classes": [
{"id": "2fc87f64-5417-4562-b3fc-2c963f66afa4"},
{"id": "7ffcada8-0215-4fb0-bea9-2266836d3b18"},
{"id": "6ee973f7-c77b-4738-b275-9a7299b9b82b"}
]
}
The closest I got was: let {id, number, enabled, classes: [{id}]} = objBefore;
But it only gets me one id in classes. I've tried spreading above using [...{id}] or [{...id}]. Same thing.
I find it challenging to get the right mental model for how to think about this when it's on multiple levels. In my mind, when I say [...{id}] I'm thinking, "I want the id property as an object in the outer classes array, but give me every id in the array!"
Clearly I'm not thinking about this correctly.
I've tried it using map to get that part but I'm still having trouble combining it back to the original to produce the desired result. for example:
let classIds = objBefore.classes.map(({id}) => {
return {
id
}
})
(Using the map syntax, how can I destructure in the function the other keys that are one level higher?)
To combine them I started trying anything and everything, :
let {id, number, enabled, classIds} = {objBefore, [...classIds]} // returns undefined for all
I'd prefer to do it in one statement. But if that's not possible, then what's a clean way to do it using map?.
You can't destructure and map at the same time in the way you're looking to do it. The main purpose of destructuring assignment is to extract data from an array/object and not for manipulating data. In your case, as you're after an object with the same keys/value as your original object, just with a different classes array, I would instead suggest creating a new object and spreading ... the original object into that. Then you can overwrite the classes array with a mapped version of that array:
const objBefore = { "id": "3pa99f64-5717-4562-b3fc-2c963f66afa1", "number": "5000", "enabled": true, "classes": [ { "id": "2fc87f64-5417-4562-b3fc-2c963f66afa4", "name": "General" }, { "id": "7ffcada8-0215-4fb0-bea9-2266836d3b18", "name": "Special" }, { "id": "6ee973f7-c77b-4738-b275-9a7299b9b82b", "name": "Limited" } ] };
const newObj = {
...objBefore,
classes: objBefore.classes.map(({id}) => ({id}))
};
console.log(newObj);
How about using simple util method with object destructuring, spread operator and map
const objBefore = {
id: "3pa99f64-5717-4562-b3fc-2c963f66afa1",
number: "5000",
enabled: true,
classes: [
{
id: "2fc87f64-5417-4562-b3fc-2c963f66afa4",
name: "General",
},
{
id: "7ffcada8-0215-4fb0-bea9-2266836d3b18",
name: "Special",
},
{
id: "6ee973f7-c77b-4738-b275-9a7299b9b82b",
name: "Limited",
},
],
};
const process = ({ classes, ...rest }) => ({
...rest,
classes: classes.map(({ id }) => ({ id })),
});
console.log(process(objBefore))
In one line, you could do this:
const objAfter = { ...objBefore, classes: objBefore.classes.map(item => ({ id: item.id })) };
Or, if you prefer:
const objAfter = {...objBefore, classes: objBefore.classes.map(({id}) => ({id}))};
There isn't any way in object destructing to copy an entire array of objects into a different array of objects by removing properties so you use .map() for that.

How to get all values of given specific keys (for e.g: name) without loop from json?

I want to fetch all the names and label from JSON without loop. Is there a way to fetch with any filter method?
"sections": [
{
"id": "62ee1779",
"name": "Drinks",
"items": [
{
"id": "1902b625",
"name": "Cold Brew",
"optionSets": [
{
"id": "45f2a845-c83b-49c2-90ae-a227dfb7c513",
"label": "Choose a size",
},
{
"id": "af171c34-4ca8-4374-82bf-a418396e375c",
"label": "Additional Toppings",
},
],
},
]
}
When you say "without loops" I take it as without For Loops. because any kind of traversal of arrays, let alone nested traversal, involve iterating.
You can use the reduce method to have it done for you internally and give you the format you need.
Try this :
const data = {
sections: [
{
id: "62ee1779",
name: "Drinks",
items: [
{
id: "1902b625",
name: "Cold Brew",
optionSets: [
{
id: "45f2a845-c83b-49c2-90ae-a227dfb7c513",
label: "Choose a size"
},
{
id: "af171c34-4ca8-4374-82bf-a418396e375c",
label: "Additional Toppings"
}
]
}
]
}
]
};
x = data.sections.reduce((acc, ele) => {
acc.push(ele.name);
otherName = ele.items.reduce((acc2, elem2) => {
acc2.push(elem2.name);
label = elem2.optionSets.reduce((acc3, elem3) => {
acc3.push(elem3.label);
return acc3;
}, []);
return acc2.concat(label);
}, []);
return acc.concat(otherName);
}, []);
console.log(x);
Go ahead and press run snippet to see if this matches your desired output.
For More on info reduce method
In the context of cJSON
yes, we can fetch the key value for any of the object.
1 - each key value is pointed by one of the objects. will simply fetch that object and from there will get the key value.
In the above case for
pre-requisition: root must contain the json format and root must be the cJSON pointer. if not we can define it and use cJSON_Parse() to parse the json.
1st name object is "sections" will use
cJSON *test = cJSON_GetObjectItem(root, "sections");
char *name1 = cJSON_GetObjectItem(test, "name" )->valuestring;
2nd name key value
cJSON *test2 = cJSON_GetObjectItem(test, "items");
char *name2 = cJSON_GetObjectItem(tes2, "name")->valuestring;
likewise, we can do for others as well to fetch the key value.

Creating an array of objects inside an object that already exists

I can create nested objects in Javascript like this:
var filter = {
filterColumns: {
value: "",
valueText:""
}
};
but how can I turn filtercolumns into an array of objects? for example I would like to be able to do this:
filter.filterColumns[26].value = "value"
filter.filterColumns[26].valueText = "Bob"
filter.filterColumns[32].value = "value"
filter.filterColumns[32].valueText = "Ibb"
etc.
Thanks
EDIT: Apologies, I got this completely wrong. My original post confused javascript with C#. I have re-written it to reflect what I am trying to do.
Do you mean something like the following?
var filter = {
filterColumns: [
{
value: "1",
valueText: "Alice"
},{
value: "2",
valueText: "Bob"
},{
value: "3",
valueText: "Charlie"
}
]
};
Now filter.filterColumns[1].valueText would contain the string "Bob";
You can for example add to the list with the following code:
filter.filterColumns.push({value: "4", valueText: "Daniel"});

Deep picking using Underscore.JS

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

Insert object into MongoDB object's array

I'm trying to add an object into an empty array that is stored in one of my collections.
Currently this is how I have my collection setup:
[
{
"name": "user_added",
"DRGs": []
},
...
]
How can I insert an object into the collection so that it looks like this;
[
{
"name": "user_added",
"DRGs": [
{
"code": "491",
"name": "Back & neck procedures"
}
]
},
...
]
Check out $push documentation.
You should be able to accomplish your goal with the following:
var collectionName = 'users'; // or whatever your actual collection name is
var objectToPush = {
code: "491",
name: "Back & neck procedures"
};
db.collection(collectionName).updateOne(
{"name": "user_added"},
{ $push: { "DRGS": objectToPush }}
);

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