Linq for TypeScript
From
https://github.com/kutyel/linq.ts
Thank you
Install
npm install linq-to-ts --saveUsage
import
import { Linq } from 'linq-to-ts';1. all
const numbers = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9];
const rst = new Linq<number>(numbers).all(x => x < 5); // => false2. any
const numbers = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9];
const rst = new Linq<number>(numbers).any(x => x < 5); // => true3. count
const strArr = ['正一郎', '清次郎', '誠三郎', '征史郎'];
const intArr = [1, 5, 8, 12, 15, 16];
const rstStr = new Linq(strArr).count(); // => 4
const rstInt = new Linq<number>(intArr).count(x => x % 2 === 0); // => 34. where & toArray
const intArr = [0, 1, 2, 3, 4];
// even number
const rst = new Linq<number>(intArr).where(x => x % 2 === 0).toArray(); // => [ 0, 2, 4 ]5. select & toArray
const parameters = [
{ ID: 5, Rate: 0.0, Name: '正一郎' },
{ ID: 13, Rate: 0.1, Name: '清次郎' },
{ ID: 25, Rate: 0.0, Name: '誠三郎' },
{ ID: 42, Rate: 0.3, Name: '征史郎' }
];
const rst = new Linq(parameters)
.select(x => { return { ID: x.ID, Name: x.Name }; }).toArray();
// =>
// [
// { ID: 5, Name: "正一郎" },
// { ID: 13, Name: "清次郎" },
// { ID: 25, Name: "誠三郎" },
// { ID: 42, Name: "征史郎" }
// ]6. selectMany
const parameters = [
{ Name: '正一郎', Numbers: [1, 2, 3] },
{ Name: '清次郎', Numbers: [1, 3, 5] },
{ Name: '誠三郎', Numbers: [2, 4, 6] },
{ Name: '征史郎', Numbers: [9, 8, 7] }
];
const rst = new Linq(parameters).selectMany(x => new Linq(x.Numbers)).toArray(); // => [1, 2, 3, 1, 3, 5, 2, 4, 6, 9, 8, 7]7. distinct
const intArr = [0, 1, 3, 3, 2];
const parameters = [
{ ID: 5, Rate: 0.0, Name: '正一郎' },
{ ID: 13, Rate: 0.1, Name: '清次郎' },
{ ID: 25, Rate: 0.0, Name: '正一郎' },
{ ID: 42, Rate: 0.3, Name: '征史郎' }
];
const rstInt = new Linq(intArr).distinct().toArray(); // => [ 0, 1, 3, 2 ]
const rstObj = new Linq(parameters).select(x => x.Name).distinct().toArray(); // => [ "正一郎", "清次郎", "征史郎" ]8. distinctBy
const data = [
{ id: 1, name: 'one', category: 'fruits', countries: ['lxsbw', 'xliecz'] },
{ id: 1, name: 'one', category: 'fruits', countries: ['Italy', 'Austria'] },
{ id: 2, name: 'two', category: 'vegetables', countries: ['Italy', 'Germany'] }
];
const rstKey = new Linq(data).distinctBy(x => x.category).toArray();
const rstKeys = new Linq(data)
.distinctBy(el => {
return { id: el.id, category: el.category };
})
.toArray();
// rstKey =>
// [
// { id: 1, name: "one", category: "fruits", countries: [ "lxsbw", "xliecz" ] },
// { id: 2, name: "two", category: "vegetables", countries: [ "Italy", "Germany" ] }
// ]
// rstKeys =>
// [
// { id: 1, name: "one", category: "fruits", countries: [ "lxsbw", "xliecz" ] },
// { id: 2, name: "two", category: "vegetables", countries: [ "Italy", "Germany" ] }
// ]9. distinctMap
interface DisType {
ID: number;
Rate: string;
Name: string;
}
const parameters = [
{ ID: 5, Rate: 0.0, Name: '正一郎' },
{ ID: 13, Rate: 0.1, Name: '清次郎' },
{ ID: 25, Rate: 0.0, Name: '正一郎' },
{ ID: 42, Rate: 0.3, Name: '征史郎' },
{ ID: 19, Rate: 0.1, Name: '清次郎' },
{ ID: 45, Rate: 0.3, Name: '征史郎' },
{ ID: 26, Rate: 0.0, Name: '正一郎' },
{ ID: 27, Rate: 0.0, Name: '正二郎' }
];
let dataC_F = new Linq<DisType>(parameters).distinctMap(x => x.Name).toArray(); // => [ "正一郎", "清次郎", "征史郎" ]
let dataC_G = new Linq<DisType>(parameters)
.distinctMap(x => {
return { Name: x.Name };
})
.toArray(); // => [ { Name: '正一郎' }, { Name: '清次郎' }, { Name: '征史郎' } ]10. first & firstOrDefault
const numbers = [1, 2, 3, 5, 7, 11];
const parameters = [
{ ID: 5, Name: '正一郎' },
{ ID: 13, Name: '清次郎' },
{ ID: 25, Name: '誠三郎' },
{ ID: 42, Name: '征史郎' }
];
const rstInt = new Linq(numbers).first(); // => 1
const rstObj = new Linq<Person>(parameters).firstOrDefault(x => x.ID === 30); // => undefined
const rstObj = new Linq<Person>(parameters).firstOrDefault(x => x.ID === 42); // => { ID: 42, Name: '征史郎' }11. remove
let numbers = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9];
console.log(numbers.length); // => 10
new Linq(numbers).remove(6);
console.log(numbers.length); // => 912. orderBy & orderByDescending
interface Person {
ID: number;
Name: string;
}
const parameters = [
{ ID: 0, Name: '正一郎' },
{ ID: 3, Name: '清次郎' },
{ ID: 2, Name: '誠三郎' },
{ ID: 5, Name: '征史郎' }
];
const rst = new Linq<Person>(parameters).orderBy(x => x.ID).toArray();
const rstDesc = new Linq<Person>(parameters).orderByDescending(x => x.ID).toArray();
// rst =>
// [
// { ID: 0, Name: "正一郎" },
// { ID: 2, Name: "誠三郎" },
// { ID: 3, Name: "清次郎" },
// { ID: 5, Name: "征史郎" }
// ]
// rstDesc =>
// [
// { ID: 5, Name: "征史郎" },
// { ID: 3, Name: "清次郎" },
// { ID: 2, Name: "誠三郎" },
// { ID: 0, Name: "正一郎" }
// ]13. thenBy & thenByDescending
interface Person {
ID: number;
Age: number;
Name: string;
}
const persons = [
{ ID: 0, Age: 30, Name: 'A' },
{ ID: 1, Age: 25, Name: 'B' },
{ ID: 2, Age: 2, Name: 'G' },
{ ID: 2, Age: 18, Name: 'C' },
{ ID: 1, Age: 30, Name: 'D' },
{ ID: 1, Age: 25, Name: 'E' },
{ ID: 2, Age: 15, Name: 'F' }
];
const rst = new Linq<Person>(persons)
.orderByDescending(x => x.ID)
.thenBy(x => x.Age)
.thenByDescending(x => x.Name).toArray();
// 1 orderByDescending =>
// [
// { ID: 2, Age: 2, Name: "G" },
// { ID: 2, Age: 18, Name: "C" },
// { ID: 2, Age: 15, Name: "F" },
// { ID: 1, Age: 25, Name: "B" },
// { ID: 1, Age: 30, Name: "D" },
// { ID: 1, Age: 25, Name: "E" },
// { ID: 0, Age: 30, Name: "A" }
// ]
// 2 thenBy =>
// [
// { ID: 2, Age: 2, Name: "G" },
// { ID: 2, Age: 15, Name: "F" },
// { ID: 2, Age: 18, Name: "C" },
// { ID: 1, Age: 25, Name: "B" },
// { ID: 1, Age: 25, Name: "E" },
// { ID: 1, Age: 30, Name: "D" },
// { ID: 0, Age: 30, Name: "A" }
// ]
// 3 thenByDescending =>
// [
// { ID: 2, Age: 2, Name: "G" },
// { ID: 2, Age: 15, Name: "F" },
// { ID: 2, Age: 18, Name: "C" },
// { ID: 1, Age: 25, Name: "E" },
// { ID: 1, Age: 25, Name: "B" },
// { ID: 1, Age: 30, Name: "D" },
// { ID: 0, Age: 30, Name: "A" }
// ]14. groupBy
interface GroupObj {
id: number;
name: string;
category: string;
countries: string[];
}
const data = [
{ id: 1, name: 'one', category: 'fruits', countries: ['lxsbw', 'xliecz'] },
{ id: 1, name: 'one', category: 'fruits', countries: ['Italy', 'Austria'] },
{ id: 2, name: 'two', category: 'vegetables', countries: ['Italy', 'Germany'] }
];
const rstKey = new Linq<GroupObj>(data).groupBy(el => el.category);
const rstKeys = new Linq<GroupObj>(data).groupBy(el => {
return { id: el.id, category: el.category };
});
// rstKey =>
// [
// {
// key: 1, count: 2,
// elements: [
// { id: 1, name: "one", category: "fruits", countries: [Array] },
// { id: 1, name: "one", category: "fruits", countries: [Array] }
// ]
// },
// {
// key: 2, count: 1,
// elements: [ { id: 2, name: "two", category: "vegetables", countries: [Array] } ]
// }
// ]
// rstKeys =>
// [
// {
// key: { id: 1, category: "fruits" }, count: 2,
// elements: [
// { id: 1, name: "one", category: "fruits", countries: [Array] },
// { id: 1, name: "one", category: "fruits", countries: [Array] }
// ]
// },
// {
// key: { id: 2, category: "vegetables" }, count: 1,
// elements: [ { id: 2, name: "two", category: "vegetables", countries: [Array] } ]
// }
// ]15. join
const persons = [
{ CityID: 1, Name: 'ABC' },
{ CityID: 1, Name: 'EFG' },
{ CityID: 2, Name: 'HIJ' },
{ CityID: 3, Name: 'KLM' },
{ CityID: 3, Name: 'NOP' },
{ CityID: 4, Name: 'QRS' },
{ CityID: 5, Name: 'TUV' }
];
const cities = [
{ ID: 1, Name: 'Guangzhou' },
{ ID: 2, Name: 'Shenzhen' },
{ ID: 3, Name: 'Beijing' },
{ ID: 4, Name: 'Shanghai' }
];
const rst = new Linq(persons)
.join(
new Linq(cities),
p => p.CityID,
c => c.ID,
(p, c) => {
return { CityID: c.ID, PersonName: p.Name, CityName: c.Name };
}
)
.toArray();
// rst =>
// [
// { CityID: 1, PersonName: "ABC", CityName: "Guangzhou" },
// { CityID: 1, PersonName: "EFG", CityName: "Guangzhou" },
// { CityID: 2, PersonName: "HIJ", CityName: "Shenzhen" },
// { CityID: 3, PersonName: "KLM", CityName: "Beijing" },
// { CityID: 3, PersonName: "NOP", CityName: "Beijing" },
// { CityID: 4, PersonName: "QRS", CityName: "Shanghai" }
// ]16. toDictionary
const parameters = [
{ ID: 0, Age: 52, Name: '正一郎' },
{ ID: 8, Age: 28, Name: '清次郎' },
{ ID: 3, Age: 20, Name: '誠三郎' },
{ ID: 4, Age: 18, Name: '征史郎' }
];
const dictionary = new Linq(parameters).toDictionary(x => x.ID).toArray();
const dictionaryObj = new Linq(parameters)
.toDictionary(x => { return { ID: x.ID, Name: x.Name }; })
.toArray();
// dictionary =>
// [
// { Key: 0, Value: { ID: 0, Age: 52, Name: "正一郎" } },
// { Key: 8, Value: { ID: 8, Age: 28, Name: "清次郎" } },
// { Key: 3, Value: { ID: 3, Age: 20, Name: "誠三郎" } },
// { Key: 4, Value: { ID: 4, Age: 18, Name: "征史郎" } }
// ]
// dictionaryObj =>
// [
// { Key: { ID: 0, Name: "正一郎" }, Value: { ID: 0, Age: 52, Name: "正一郎" } },
// { Key: { ID: 8, Name: "清次郎" }, Value: { ID: 8, Age: 28, Name: "清次郎" } },
// { Key: { ID: 3, Name: "誠三郎" }, Value: { ID: 3, Age: 20, Name: "誠三郎" } },
// { Key: { ID: 4, Name: "征史郎" }, Value: { ID: 4, Age: 18, Name: "征史郎" } }
// ]17. sum
interface Person {
Age: number;
Name: string;
}
const parameters = [
{ Age: 52, Name: '正一郎' },
{ Age: 28, Name: '清次郎' },
{ Age: 20, Name: '誠三郎' },
{ Age: 18, Name: '征史郎' }
];
const rst = new Linq<Person>(parameters).sum(x => x.Age); // => 11818. max
interface Person {
Age: number;
Name: string;
}
const parameters = [
{ Age: 52, Name: '正一郎' },
{ Age: 28, Name: '清次郎' },
{ Age: 20, Name: '誠三郎' },
{ Age: 18, Name: '征史郎' }
];
const rst = new Linq<Person>(parameters).max(x => x.Age); // => 5219. min
interface Person {
Age: number;
Name: string;
}
const parameters = [
{ Age: 52, Name: '正一郎' },
{ Age: 28, Name: '清次郎' },
{ Age: 20, Name: '誠三郎' },
{ Age: 18, Name: '征史郎' }
];
const rst = new Linq<Person>(parameters).min(x => x.Age); // => 1820. take
const texts = ['Sun', 'Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat'];
const rst = new Linq(texts).take(4).toArray(); // => [ "Sun", "Mon", "Tue", "Wed" ]21. skip
const texts = ['Sun', 'Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat'];
const rst = new Linq(texts).skip(4).toArray(); // => [ "Thu", "Fri", "Sat" ]Documentation
If you do not know Linq or just want to remember what is all about, have a look at the docs.
Contributors
Thanks goes to these wonderful people (emoji key):
This project follows the all-contributors specification. Contributions of any kind welcome!
License
MIT