I understand how to sort an an array of objects by one property, but not how to re-sort the array again alphabetically (while keeping the sorting by property).
For example, I have an array:
[
{title: 'Hello', category: 'something'},
{title: 'Good', category: 'something else'},
{title: 'Monday', category: 'something'},
{title: 'Evening', category: 'something'}, {title: 'Food', category: 'others'}
]
To sort the array by category:
array.sort(
(a, b) => -b.category.localeCompare(a.category)
)
However, how can I sort the items in each category alphabetically, in this array, while keeping the elements sorted by the category?
If localeCompare returns 0, compare another field
const array = [{
title: 'Hello',
category: 'something'
},
{
title: 'Good',
category: 'something else'
},
{
title: 'Monday',
category: 'something'
},
{
title: 'Evening',
category: 'something'
}, {
title: 'Food',
category: 'others'
}
]
array.sort(
(a, b) => {
const category = -b.category.localeCompare(a.category)
if (category) return category
return a.title.localeCompare(b.title)
}
)
console.log(array)
Related
const array = [{
id: 1,
name: 'test',
attrs: [{
name: 'Attribute 1',
description: 'Description 1',
}],
values: [{
name: 'value 1',
attrs: [{
name: 'Attribute 1',
type: 'Type 1',
},
{
name: 'Attribute 2',
type: 'Type 2',
},
],
}, ],
}, ];
const newArray =
array.map((item) => {
return {
...item,
isNegative: true
};
});
console.log(newArray);
I receive data as displayed in the const array. I need to push a value 'isNegative' to array[].attrs and to each values.attrs. I'm only able to do it to the array[].attrs. How can I do it to the others?
You're only mapping over the top-level array. If you need to map over the arrays within each object, that's another call to .map(). For example:
const array = [{
id: 1,
name: 'test',
attrs: [{
name: 'Attribute 1',
description: 'Description 1',
}],
values: [{
name: 'value 1',
attrs: [{
name: 'Attribute 1',
type: 'Type 1',
},
{
name: 'Attribute 2',
type: 'Type 2',
},
],
}, ],
}, ];
const newArray =
array.map((item) => {
return {
...item,
isNegative: true,
attrs: item.attrs.map((attr) => {
return {
...attr,
isNegative: true
}
})
};
});
console.log(newArray);
Same with the values property, any array within objects in values, etc. Any array that you want to map to a new structure, call .map() on it.
This question already has answers here:
Group by count of objects within an array in Vanilla Javascript
(4 answers)
Closed 11 months ago.
What i mean is, imagine i have this data
const data = [
{ name: 'Apple', category: 'fruit' },
{ name: 'Orange', category: 'fruit' },
{ name: 'Banana', category: 'fruit' },
{ name: 'Milk', category: 'drink' },
{ name: 'Juice', category: 'drink' },
];
What i want is to show unique categories and show number of same items
[
{ count: 3, category: 'fruit' },
{ count: 2, category: 'drink' },
]
One Solution is leveraging JS Set to find out unique category and use it to get the count.
const data = [
{ name: 'Apple', category: 'fruit' },
{ name: 'Orange', category: 'fruit' },
{ name: 'Banana', category: 'fruit' },
{ name: 'Milk', category: 'drink' },
{ name: 'Juice', category: 'drink' },
];
const categories = new Set();
data.forEach((item) => {
categories.add(item.category);
})
const result = [];
categories.forEach((category) => {
const val = data.filter((item) => item.category === category);
result.push({count: val.length, category})
})
console.log(result);
I don't know if this is the right way to do but it should work
const data = [
{ name: 'Apple', category: 'fruit' },
{ name: 'Orange', category: 'fruit' },
{ name: 'Banana', category: 'fruit' },
{ name: 'Milk', category: 'drink' },
{ name: 'Juice', category: 'drink' },
];
function filterArray(arr) {
const map = new Map()
arr.map(i => map.set(i.category, map.get(i.category) + 1 || 1))
return [...map].map(i => ({'count': i[1],'category': i[0]}))
}
let result = filterArray(data)
console.log(result)
This question already has answers here:
How to sort an object array by date property?
(25 answers)
Closed 2 years ago.
i have data like below,
const subItems = [
{
id: '1',
title: 'subitem-one',
status: 'new',
createdAt: '2020-08-13T16:32:10.000Z',
orders: [
{
id: '1',
title: 'subitem1-order-one',
status: 'new',
},
{
id: '2',
title: 'subitem1-order-two',
status: 'new',
},
]
},
{
id: '2',
title: 'subitem-two',
status: 'new',
createdAt: '2020-08-16T12:02:06.000Z',
orders: [
{
id: '2',
title: 'subitem2-order-one',
status: 'new',
},
],
},
]
how can i sort the subItems array of objects in ascending order based on createdAt property using javascript.
expected output is as below,
const subItems = [
{
id: '1',
title: 'subitem-one',
status: 'new',
createdAt: '2020-08-16T16:32:10.000Z',
orders: [
{
id: '1',
title: 'subitem1-order-one',
status: 'new',
},
{
id: '2',
title: 'subitem1-order-two',
status: 'new',
},
]
},
{
id: '2',
title: 'subitem-two',
status: 'new',
createdAt: '2020-08-13T12:02:06.000Z',
orders: [
{
id: '2',
title: 'subitem2-order-one',
status: 'new',
},
],
},
]
how can i do sort the data in ascending order based on createdAt. the most recently created should be first. could someone help me with this. thanks.
You s´can simply use the sort function with the callback:
const sortedItems = subItems.sort((a,b) => b.createdAt.localeCompare(a.createdAt))
Ascending
subItems.sort((a,b)=>new Date(a.createdAt) - new Date(b.createdAt))
Descending
subItems.sort((a,b)=>new Date(b.createdAt) - new Date(a.createdAt))
Use the Array#sort function with a callback for your sort-algorithm.
function sortSubItems(subItems) {
subItems.sort((a,b) => {
a= (new Date(a.createdAt)).getTime();
b= (new Date(b.createdAt)).getTime();
return b-a;
});
return subItems;
}
const subItems = [
{
id: '1',
title: 'subitem-one',
status: 'new',
createdAt: '2020-08-13T16:32:10.000Z',
orders: [
{
id: '1',
title: 'subitem1-order-one',
status: 'new',
},
{
id: '2',
title: 'subitem1-order-two',
status: 'new',
},
]
},
{
id: '2',
title: 'subitem-two',
status: 'new',
createdAt: '2020-08-16T12:02:06.000Z',
orders: [
{
id: '2',
title: 'subitem2-order-one',
status: 'new',
}
]
},
];
console.log(sortSubItems(subItems));
If I have an array where each object has a neste object:
items: [
{
id: 1,
name: Tomato
category: {
id: 1,
name: Vegetable
}
},
{
id: 2,
name: Apple
category: {
id: 2,
name: Fruit
}
}
]
How do I get a new array with the field name of the nested object merged in the parent array?
items_extended: [
{
id: 1,
name: Tomato
category: Vegetable
},
{
id: 2,
name: Apple
category: Fruit
}
]
You can map through the array and return a modified version.
var items_extended = items.map(function (item) {
return {
id: item.id,
name: item.name,
category: item.category.name,
};
});
I have an array, which I want to filter with another array. My goal is to filter the array with two values and I want the result with only matching exactly this two values. This is what I have so far:
const array = [
{
title: 'Title A',
someOtherProps: [
'AAA',
]
}, {
title: 'Title B',
someOtherProps: [
'AAA',
'BBB',
]
}, {
title: 'Title C',
someOtherProps: [
'BBB',
'CCC'
]
}, {
title: 'Title D',
someOtherProps: [
'BBB',
]
}, {
title: 'Title E',
someOtherProps: [
'CCC'
]
},
]
const filter = [
'AAA',
'BBB',
]
let result = array.filter(obj => obj.someOtherProps.some(props => filter.includes(props)))
console.log(result);
So my result has Objects with my filtered value.
// My Result
{
title: 'Title A'
someOtherProps: [
'AAA',
]
}, {
title: 'Title B'
someOtherProps: [
'AAA',
'BBB',
]
}, {
title: 'Title C'
someOtherProps: [
'BBB',
'CCC'
]
}, {
title: 'Title D'
someOtherProps: [
'BBB',
]
}
So far so good. But I dont need all objects, which has one of the values. I need the object, which has exactly these two values combined.
// Wanted Result
{
title: 'Title B'
someOtherProps: [
'AAA',
'BBB',
]
}
I cant find a way. I know how to get the difference of two arrays. But I need the difference of two values, if you know what I mean.
Use Array#every() on filter array and check its all values are included in the someOtherProps of object.
You can use Array#find() for that purpose if you want only one object
const array = [ { title: 'Title A', someOtherProps: [ 'AAA', ] }, { title: 'Title B', someOtherProps: [ 'AAA', 'BBB', ] }, { title: 'Title C', someOtherProps: [ 'BBB', 'CCC' ] }, { title: 'Title D', someOtherProps: [ 'BBB', ] }, { title: 'Title E', someOtherProps: [ 'CCC' ] }, ]
const filter = ['AAA','BBB',]
let res = array.find(x => filter.every( a => x.someOtherProps.includes(a)));
console.log(res)
If you want all the elements that matches the condition then use filter().
const array = [ { title: 'Title A', someOtherProps: [ 'AAA', ] }, { title: 'Title B', someOtherProps: [ 'AAA', 'BBB', ] }, { title: 'Title C', someOtherProps: [ 'BBB', 'CCC' ] }, { title: 'Title D', someOtherProps: [ 'BBB', ] }, { title: 'Title E', someOtherProps: [ 'CCC' ] }, ]
const filter = ['AAA','BBB',]
let res = array.filter(x => filter.every( a => x.someOtherProps.includes(a)));
console.log(res)
Change with this:
array.filter(x => filter.every( a => x.someOtherProps.includes(a)));