Develop Reference

Return last value with recursion - Javascript

Hi all I have following data:
const section = {
fileds: [
{ id: "some Id-1", type: "user-1" },
{
child: [
{ id: "some Id-2", type: "user-2" },
{ fileds: [{ id: "kxf5", status: "pending" }] },
{ fileds: [{ id: "ed5t", status: "done" }] }
]
},
{
child: [
{ id: "some Id-3", type: "teacher" },
{ fileds: [{ id: "ccfr", status: null }] },
{ fileds: [{ id: "kdpt8", status: "inProgress" }] }
]
}
]
};
and following code:
const getLastIds = (arr) =>
arr.flatMap((obj) => {
const arrayArrs = Object.values(obj).filter((v) => Array.isArray(v));
const arrayVals = Object.entries(obj)
.filter(([k, v]) => typeof v === "string" && k === "id")
.map(([k, v]) => v);
return [...arrayVals, ...arrayArrs.flatMap((arr) => getLastIds(arr))];
});
console.log(getLastIds(section.fileds));
// output is (7) ["some Id-1", "some Id-2", "kxf5", "ed5t", "some Id-3", "ccfr", "kdpt8"]
My code doing following, it printing in new array all ids.
It's working but I don't need all ids.
I need to return only last id in array and I should use recursion.
The output should be
(4) [" "kxf5", "ed5t", "ccfr", "kdpt8"]
P.S. here is my code in codesandbox
Is there a way to solve this problem with recursion? Please help to fix this.

You can do it with reduce.
function getLastIds (value) {
return value.reduce((prev, cur) => {
if (cur.id) {
return [ ...prev, cur.id ];
} else {
let key = ('child' in cur) ? 'child' : 'fileds';
return [ ...prev, ...getLastIds (cur[key]) ]
}
}, []);
}

You could check if a certain key exists and take this property for mapping id if status exists.
const
getValues = data => {
const array = Object.values(data).find(Array.isArray);
return array
? array.flatMap(getValues)
: 'status' in data ? data.id : [];
},
section = { fileds: [{ id: "some Id-1", type: "user-1" }, { child: [{ id: "some Id-2", type: "user-2" }, { fileds: [{ id: "kxf5", status: "pending" }] }, { fileds: [{ id: "ed5t", status: "done" }] }] }, { child: [{ id: "some Id-3", type: "teacher" }, { fileds: [{ id: "ccfr", status: null }] }, { fileds: [{ id: "kdpt8", status: "inProgress" }] }] }] },
result = getValues(section);
console.log(result);

How to add multiple ids and content?

Javascript
In a constructor and I want to manipulate it and want to add as many ids and content as much as I want.
var groups = new vis.DataSet([
{ id: 1, content: "" },
{ id: 2, content: "" },
{ id: 3, content: "" },
{ id: 4, content: "" },
]);

I am not 100% sure what you're asking for, so here are two solutions.
As Insyri mentioned in the comments, you should utilize the spread syntax. You could do something along the lines of this:
var groups = [
{ id: 1, content: 'abc' },
{ id: 2, content: 'cba' },
{ id: 3, content: '123' },
{ id: 4, content: '321' },
];
class someClass {
constructor(...data) {
this.key = data;
}
}
const test = new someClass(...groups);
console.log(test)
The output of the console log will look like this:
someClass {
key: [
{ id: 1, content: 'abc' },
{ id: 2, content: 'cba' },
{ id: 3, content: '123' },
{ id: 4, content: '321' }
]
}
If you want all of the objects to have a unique key (of whatever you want), you can do this:
class otherClass {
constructor(...data) {
data.forEach(obj=>{
this[obj.id] = obj
})
}
}
const test2 = new otherClass(...groups);
console.log(test2)
Output:
otherClass {
'1': { id: 1, content: 'abc' },
'2': { id: 2, content: 'cba' },
'3': { id: 3, content: '123' },
'4': { id: 4, content: '321' }
}

Filter array inside array

I have the array as below
test_list = [
{
id: 1,
test_name: 'Test 1',
members: [
{
user_id: 3
},
{
user_id: 4
}
],
},
{
id: 2,
test_name: 'Test 2',
members: [
{
user_id: 4
},
{
user_id: 5
},
],
},
{
id: 3,
test_name: 'Test 2',
members: [
{
user_id: 8
},
{
user_id: 10
},
],
}
]
I want to filter the test for specific user_id, example if user_id = 4 I would like to have this result
{
id: 1,
...
},
{
id: 2,
...
},
I have tried with this but it only return the member
test_list.filter(function(item) {
item.members.filter(function(member) {
if(member.user_id === 4) {
return item;
}
});
})
Would anyone please help me in this case?

Check if .some of the objects in the members array have the user_id you're looking for:
test_list = [{
id: 1,
test_name: 'Test 1',
members: [{
user_id: 3
},
{
user_id: 4
}
],
},
{
id: 2,
test_name: 'Test 2',
members: [{
user_id: 4
},
{
user_id: 5
},
],
},
{
id: 3,
test_name: 'Test 2',
members: [{
user_id: 8
}]
}
];
const filtered = test_list.filter(
({ members }) => members.some(
({ user_id }) => user_id === 4
)
);
console.log(filtered);

You could use .reduce() and .filter() method of array to achieve required result.
Please check below working code snippet:
const arr = [{"id":1,"test_name":"Test 1","members":[{"user_id":3},{"user_id":4}]},{"id":2,"test_name":"Test 2","members":[{"user_id":4},{"user_id":5}]},{"id":3,"test_name":"Test 2","members":[{"user_id":8}]}];
const data = arr.reduce((r,{ members,...rest }) => {
let rec = members.filter(o => o.user_id === 4)
if(rec.length){
rest.members = rec;
r.push(rest);
}
return r;
},[]);
console.log(data);

Hope this works.
var members = item.members;
var filterById =members.filter((item1)=>{
return (item1.user_id===4)
});
return filterById.length > 0;
});
console.log(test_List_by_id)```

How to convert json to tree array in JS?

I would like to convert this json / object to this specific structure below to allow me to use a treeList component.
I've tried to build a recursive function but I didn't find the solution yet.
Thanks for your help
const data = {
parent1: {
child1: { bar: "1" },
child2: "2"
},
parent2: {
child1: "1"
}
}
to
const treeData = [
{
title: "parent1",
key: "parent1",
children: [
{
title: "child1",
key: "child1",
children: [{ title: "bar", key: "bar", value: "1" }]
},
{
title: "child2",
key: "child2",
value: "2"
}
],
},
{
title: "parent2",
key: "parent2",
children: [
{
title: "child1",
key: "child1",
value: "1"
}
]
}
]

You could take an iterative and recursive approach.
function getNodes(object) {
return Object
.entries(object)
.map(([key, value]) => value && typeof value === 'object'
? { title: key, key, children: getNodes(value) }
: { title: key, key, value }
);
}
const data = { parent1: { child1: { bar: "1" }, child2: "2" }, parent2: { child1: "1" } },
result = getNodes(data);
console.log(result);
.as-console-wrapper { max-height: 100% !important; top: 0; }

just share sample, a little different from yours. But it give you a hint with recursive function.
https://jsfiddle.net/segansoft/7bdxmys4/1/
function getNestedChildren(arr, parent) {
var out = []
for (var i in arr) {
if (arr[i].parent == parent) {
var children = getNestedChildren(arr, arr[i].id)
if (children.length) {
arr[i].children = children
}
out.push(arr[i])
}
}
return out
}
var flat = [{
id: 1,
title: 'hello',
parent: 0
},
{
id: 2,
title: 'hello',
parent: 0
},
{
id: 3,
title: 'hello',
parent: 1
},
{
id: 4,
title: 'hello',
parent: 3
},
{
id: 5,
title: 'hello',
parent: 4
},
{
id: 6,
title: 'hello',
parent: 4
},
{
id: 7,
title: 'hello',
parent: 3
},
{
id: 8,
title: 'hello',
parent: 2
}
]
var nested = getNestedChildren(flat, 0)
document.write('<pre>' + JSON.stringify(nested, 0, 4) + '</pre>');

Testing a mocked Observable converted to a promise in Angular

I have a Angular service I want to test, one get function returns transformed data:
getSomeThings(pageSize) {
return this.http
.get(`../assets/things.json`)
.map((response) => response.json())
.toPromise()
.then(response => {
return response.map((thing) => {
return new Thing(thing);
});
}).then(response => {
response.slice(0, pageSize)
});
}
}
I'm testing this as below:
describe('ThingsService', () => {
let service: ThingsService;
let mockHttp;
const things = [{ id: 1, title: 'hello' }, { id: 2, title: 'hello' }, { id: 3, title: 'hello' }, { id: 4, title: 'hello' },
{ id: 5, title: 'hello' }, { id: 6, title: 'hello' }, { id: 7, title: 'hello' }, { id: 8, title: 'hello' }, { id: 9, title: 'hello' },
{ id: 10, title: 'hello' }, { id: 11, title: 'hello' }, { id: 12, title: 'hello' }];
beforeEach(() => {
mockHttp = new Http(undefined, undefined)
service = new ThingsService(mockHttp);
spyOn(mockHttp, 'get').and.returnValue(Observable.of(things)).and.callThrough();
});
it('should have a length of 10', async(() => {
mockHttp.get.and.returnValue(Observable.of(things));
return service.getThings(10)
.then((returnedThings: any[]) => {
expect(returnedThings.length).toBe(10)
});
}));
});
This returns an error:
response.json is not a function
things[] has a length of 12, but there's a slice in the final then() which should only return 10.
I'm quite new to Jasmine so could've easily missed some fundamentals here. Any help appreciated

const things = {
json:function(){
return [{ id: 1, title: 'hello' }, { id: 2, title: 'hello' }, { id: 3, title: 'hello' }, { id: 4, title: 'hello' },
{ id: 5, title: 'hello' }, { id: 6, title: 'hello' }, { id: 7, title: 'hello' }, { id: 8, title: 'hello' }, { id: 9, title: 'hello' },
{ id: 10, title: 'hello' }, { id: 11, title: 'hello' }, { id: 12, title: 'hello' }];
}
}