This question already has answers here:
Convert list of Objects when the levels are given in an array
(2 answers)
Populate nested object from array?
(2 answers)
Closed 3 years ago.
What's the best way to create a N levels nested object (where N is the size of the array) for example:
const arr = ['a','b','c','d']
The output object should look like this:
{
a: {
b: {
c: {
d: true
}
}
}
}
You can use array.reduce, it helps you pass an accumulator where you can accumulate your nested obj.
const array = ['a','b','c','d'];
const object = {};
array.reduce((o, s) => {
return o[s] = {};
}, object);
console.log(object);
Related
This question already has answers here:
Converting JavaScript object with numeric keys into array
(17 answers)
How to convert an Object {} to an Array [] of key-value pairs in JavaScript
(21 answers)
Closed 10 months ago.
I have an object with these key-value pairs. This object comes from an API which I am calling :
APIName(obj).subscribe((res:any) => {
console.log(Object.values(res.data));
})
data = {
0 : 1,
1: 3,
2: 7,
3: 10
....so on
}
simply put it is an object of numbers and my desired output is (a simple array) :
data = [1,3,7,10]
I've tried Object.value and Object.key it still converts it into an object. Any help?
First of all if your data is not sorted by key. Then sort it. and iterate through object and push to array.
var data = {
1: 1,
0: 3,
2: 7,
3: 10
};
let sortedKeys = Object.keys(data).sort();
let arrayOfData = [];
// iterate method
sortedKeys.forEach((key) => {
arrayOfData.push(data[key]);
});
console.log(arrayOfData);
This question already has answers here:
How do you JSON.stringify an ES6 Map?
(16 answers)
How to serialize a Map in javascript?
(3 answers)
Closed last year.
Why does this map print empty? I'd expect it to be populated from the array? I'm probably missing something small.
let numbers = [1, 2, 3];
let numberMap = numbers.reduce((map, obj) => {
return map.set(obj, obj + 1);
}, new Map());
console.log(JSON.stringify(numberMap));
This question already has answers here:
Merge keys array and values array into an object in JavaScript
(14 answers)
merge two arrays (keys and values) into an object [duplicate]
(3 answers)
Closed 2 years ago.
Platform: ReactJS
I am trying to combine the two arrays as a date:value object. Any thoughts?
a=["1/1/2020", "1/2/2020", "1/3/2020", "1/4/2020"]
b = [ 1, 2, 3, 4 ]
I am looking for the following result:
["1/1/2020":1, "1/2/2020":2, "1/3/2020":3, "1/4/2020":4]
Thank you,
You can try this approach.
const a=["1/1/2020", "1/2/2020", "1/3/2020", "1/4/2020"]
const b = [ 1, 2, 3, 4 ]
const c = {};
a.forEach((v, i) => {
c[v] = b[i]
});
console.log(c);
This question already has answers here:
One-liner to take some properties from object in ES 6
(12 answers)
Elegant way to copy only a part of an object [duplicate]
(7 answers)
Closed 4 years ago.
I want to create a new object based on anther object but with fewer properties.
I know I can do it by manually assigment like this:
const obj = {
a: 1,
b: 2,
c: 3
};
const smallObj = {
a: obj.a
};
console.log(smallObj)
Is there a way to do it with destructuring?
I have tried doing this:
const obj = {
a: 1,
b: 2,
c: 3
};
const smallObj = {
a
} = {...obj}
console.log(smallObj, a)
But as you can see, I get the variable a to be equal to 1 but smallObj is a reference to obj.
This question already has answers here:
How to combine an array in javascript
(3 answers)
Closed 6 years ago.
I have an array of objects:
var arr = [
{number: "AL-32021611", b: "7500"},
{number: "AL-32021612", b: "Continental"},
{number: "AL-32021612", b: "R3"},
{number: "AL-32021612", b: "7500"}
];
Is there a way that I can get all the number coincidences and get insted of number values the 'b' values in a var?
for example
//loop
result = ["Continental", "R3", "7500"]
what i want is for example i recive the number and then i search all the coincidences with that number value and what i exactly need is all the values from the coincidences
Using ES6 features:
let result = Array.from(new Set(arr.map(el => el.b)));
or
let result = [...new Set(arr.map(el => el.b))];
Array.from()
Set
Array.prototype.map()
Arrow Functions
Spread Operator ...
Str has a nice one-line answer for you, but you can also do it explicitly with a simple for loop. See below.
As you have it,
result = {"Continental", "R3" , "7500"};
is not a valid object. You could use a for loop and push the b values into a new array that would look like:
result = ["Continental", "R3" , "7500"];
Your for loop would look like:
var result = [];
for(var n of arr) {
result.push(arr[n].b);
}
return result;