fancy-collections is a small library easing most common operations on collections. 100% type safe. Extremely user-friendly API
Key Features:
- No More Type Casting: Complex collection operations no longer require tedious and error-prone type casts.
fancy-collectionsmaintains type integrity throughout, making your code cleaner and safer. - High Reusability:
fancy-collectionseliminates the need for collection-specific lambdas, allowing you to apply common-purpose functional-style helpers across various types of collections with ease.
Why not lodash?
- Extremely strict typing -
lodashis not even close - Super developer-friendly API
- Few helpers, a lot of functionality
To get started with fancy-collections, simply install the package using npm:
npm install fancy-collectionsOr, if you're a Yarn enthusiast:
yarn add fancy-collectionscreateDict is the Marie Kondo of arrays, turning them into neatly indexed dictionaries, with an optional penchant for grouping like a fastidious collector.
import { createDict } from 'fancy-collections'
// Basic usage:
const users = [
{ id: 1, name: 'Alice' },
{ id: 2, name: 'Bob' },
]
const usersByIdDict = createDict(users, 'id')
// Result: { 1: { id: 1, name: 'Alice' }, 2: { id: 2, name: 'Bob' } }
// Advanced usage with nested paths and multiple categories:
const products = [
{ id: 1, category: { name: 'books' }, title: 'TypeScript Handbook' },
{ id: 2, category: { name: 'books' }, title: 'JavaScript: The Good Parts' },
{ id: 3, category: { name: 'electronics' }, title: 'Smartphone' },
{ id: 4, category: { name: 'groceries' }, title: 'Organic Apples' },
]
const productsTitlesByCategoriesDict = createDict(products, 'category.name', {
pathToMapTo: 'title',
shouldGroupSameKeyValues: true,
useMap: true,
})
// Result: Map {
// 'books' => ['TypeScript Handbook', 'JavaScript: The Good Parts'],
// 'electronics' => ['Smartphone'],
// 'groceries' => ['Organic Apples']
// }In createGetByKey, keys play a game of hide and seek; missing ones are met with a polite but firm error, akin to a raised eyebrow in text form.
import { createGetByKey } from 'fancy-collections'
// Example with simple path:
const users = [
{ name: 'Alice', age: 30 },
{ name: 'Bob', age: 25 },
]
const getUsersByName = createGetByKey(users, 'name')
const userByName = getUsersByName('Alice')
// Result: { name: 'Alice', age: 30 }
// Example with nested path:
const usersWithAddress = [
{ name: 'Alice', age: 30, address: { city: 'New York' } },
{ name: 'Bob', age: 25, address: { city: 'Los Angeles' } },
{ name: 'Eve', age: 28, address: { city: 'New York' } },
]
const getUserByCity = createGetByKey(usersWithAddress, 'address.city')
const userByCity = getUserByCity('New York')
// Result: { name: 'Eve', age: 28, address: { city: 'New York' } }
// Advanced usage with additional parameters:
const getUserByNameOrError = createGetByKey(users, 'name', {
errorMsg: 'User not found',
})
try {
const user = getUserByNameOrError('Charlie')
} catch (error) {
console.log(error) // Logs 'User not found'
}
const getUsersByCity = createGetByKey(usersWithAddress, 'address.city', {
shouldGroupSameKeyValues: true,
})
const usersByCity = getUsersByCity('New York')
// Result: [{ name: 'Alice', age: 30, address: { city: 'New York' } }, { name: 'Eve', age: 28, address: { city: 'New York' } }]get: The magnifying glass for object properties. It fetches values hiding in plain sight or nested deeper than a mole in its burrow. A fallback parameter stands by, like an understudy, ready to take the stage should the primary actor (the value) be missing.
import { get } from 'fancy-collections'
const user = { name: 'Alice', data: { address: { city: 'Wonderland' } } }
const city = get(user, 'data.address.city', 'Unknown')
// Result: 'Wonderland'pluck: The Swiss Army knife for navigating the nested neighborhoods of an object. It's a curried multi-tool, allowing you to remain comfortably at the object level while peering into its depths. When called with a path (and an optional fallback), it hands you a toolbox with four helpers: map, get, filter, sort.
A curried convenience store version of get(), ideal for use within Array.map().
// utils.ts
export const pluckAge = pluck('age')
export const pluckLocation = pluck('details.location')
// Using pluck().get()
const users = [
{ name: 'Alice', age: 30, details: { location: 'CityA' } },
{ name: 'Bob', age: 25, details: { location: 'CityB' } },
]
const ages = users.map(pluckAge.get)
// Result: [30, 25]
// Complex usage with nested path
const locations = users.map(pluckLocation.get)
// Result: ['CityA', 'CityB']
// Native TypeScript alternative
// Simple usage
const nativeAges = users.map((user) => user.age)
// Complex usage with nested path
const nativeLocations = users.map((user) => user.details.location)For sieving collections by nested field values, tailor-made for Array.filter(), Array.every(), Array.some().
//utils.ts
export const isGreaterThan =
(compareWith: number) =>
(x: number): boolean =>
x > compareWith
export const isGreateThan25 = isGreaterThan(25)
export const isEqualToString =
(needle: string) =>
(x: string): boolean =>
needle === x
export const isInCityA = isEqualToString('CityA')
// Using pluck().filter()
const filteredUsers = users.filter(pluckAge.filter(isGreateThan25))
// Result: [{ name: 'Alice', age: 30, details: { location: 'CityA' } }]
// Complex usage with nested path
const filteredByLocation = users.filter(pluckLocation.filter(isInCityA))
// Result: [{ name: 'Alice', age: 30, details: { location: 'CityA' } }]
// Native TypeScript alternative
// Simple usage
const nativeFiltered = users.filter((user) => user.age > 25)
// Complex usage with nested path
const nativeFilteredByLocation = users.filter(
(user) => user.details.location === 'CityA'
)A sorting wizard, ready to bring order to collections within Array.sort().
//utils.ts
export const compareStrings = (a: string, b: string): number =>
a.localeCompare(b)
export const pluckName = pluck('name')
// Using pluck().sort()
const sortedUsers = [...users].sort(pluckName.sort(compareNames))
// Result: [{ name: 'Alice', age: 30, details: { location: 'CityA' } }, { name: 'Bob', age: 25, details: { location: 'CityB' } }]
// Complex usage with nested path
const sortedByLocation = [...users].sort(pluckLocation.sort(compareStrings))
// Result: sorted array by location
// Native TypeScript alternative
// Simple usage
const nativeSorted = [...users].sort((a, b) => a.name.localeCompare(b.name))
// Complex usage with nested path
const nativeSortedByLocation = [...users].sort((a, b) =>
a.details.location.localeCompare(b.details.location)
)The precision artist for object transformation, ideal for surgical edits within Array.map().
//utils.ts
export const incrementBy =
(a: number) =>
(b: number): number =>
a + b
export const incrementBy1 = incrementBy(1)
export const toUpperCase = (str: string): string => str.toUpperCase()
// Using pluck().map()
const updatedUsers = users.map(pluckAge.map(incrementBy1))
// Result: [{ name: 'Alice', age: 31, details: { location: 'CityA' } }, { name: 'Bob', age: 26, details: { location: 'CityB' } }]
// Complex usage with nested path
const updatedLocations = users.map(pluckLocation.map(toUpperCase))
// Result: [{ name: 'Alice', age: 30, details: { location: 'CITYA' } }, { name: 'Bob', age: 25, details: { location: 'CITYB' } }]
// Native TypeScript alternative
// Simple usage
const nativeUpdated = users.map((user) => ({ ...user, age: user.age + 1 }))
// Complex usage with nested path
const nativeUpdatedLocations = users.map((user) => ({
...user,
details: { ...user.details, location: user.details.location.toUpperCase() },
}))mathesString: A precision tool in your string-matching toolbox, turning every character comparison into an amusing game of 'spot the difference'.
import { matchesString } from 'fancy-collections'
// The standard approach, for the non-fussy types
const matchHello = matchesString('Hello')
console.log(matchHello('Hello World')) // true
console.log(matchHello('Hi there')) // false
// For the case-sensitive, detail-oriented folks
const matchHelloCaseSensitive = matchesString('hello', { caseSensitive: true })
console.log(matchHelloCaseSensitive('Hello')) // false
console.log(matchHelloCaseSensitive('hello')) // true
// When you demand an exact match, because close enough isn't good enough
const matchFullString = matchesString('Hello', { matchFull: true })
console.log(matchFullString('Hello World')) // false
console.log(matchFullString('Hello')) // trueA master key for nested treasures, matchesPluckedStrings delves into the depths of data structures, unearthing matches with the finesse of an archaeologist. Craft your own universal decoders like matchesNameIdDescription and watch complex data structures yield their secrets with ease.
import { matchesPluckedStrings } from 'fancy-collections'
const products = [
{
id: '123',
name: 'SuperWidget',
description: 'The ultimate widget',
details: { category: 'Widgets' },
},
{
id: '456',
name: 'MegaGadget',
description: 'A revolutionary gadget',
details: { category: 'Gadgets' },
},
]
// Filtering products based on multiple fields
const matchProductFields = matchesPluckedStrings([
'id',
'name',
'description',
'details.category',
] as const)
// Case-insensitive partial match by default
const matchCaseInsensitive = matchProductFields('widget')
const caseInsensitiveMatches = products.filter(matchCaseInsensitive)
console.log(caseInsensitiveMatches) // [{ id: '123', name: 'SuperWidget', description: 'The ultimate widget', details: { category: 'Widgets' } }, { id: '456', name: 'MegaGadget', description: 'A revolutionary gadget', details: { category: 'Gadgets' } }]
// Case-sensitive full match
const matchCaseSensitiveFull = matchProductFields('SuperWidget', {
opts: { caseSensitive: true, matchFull: true },
})
const caseSensitiveFullMatches = products.filter(matchCaseSensitiveFull)
console.log(caseSensitiveFullMatches) // { id: '123', name: 'SuperWidget', description: 'The ultimate widget', details: { category: 'Widgets' } }The grand unifier, and wields logic like a conductor with an orchestra, orchestrating complex symphonies of conditions. Combine it with matchesPluckedStrings for a performance that makes even the most intricate data dance to your tune.
import { and, matchesPluckedStrings } from 'fancy-collections'
const products = [
{
id: '123',
name: 'SuperWidget',
description: 'The ultimate widget',
details: { category: 'Widgets' },
},
{
id: '456',
name: 'MegaGadget',
description: 'A revolutionary gadget',
details: { category: 'Gadgets' },
},
]
const matchWidget = matchesPluckedStrings(['name'] as const)('widget')
const matchGadgetsCategory = matchesPluckedStrings([
'details.category',
] as const)('Gadgets')
const widgetAndGadgetsCategory = products.filter(
and(matchWidget, matchGadgetsCategory)
)
console.log(widgetAndGadgetsCategory) // Filters products that are widgets and in the Gadgets categoryThe contrarian of the group, not turns your conditions on their head with a mischievous wink. It's the twist in your logical tale, ensuring that what you don't want is as clear as what you do.
import { not, matchesPluckedStrings } from 'fancy-collections'
const products = [
{
id: '123',
name: 'SuperWidget',
description: 'The ultimate widget',
details: { category: 'Widgets' },
},
{
id: '456',
name: 'MegaGadget',
description: 'A revolutionary gadget',
details: { category: 'Gadgets' },
},
]
const matchGadget = matchesPluckedStrings(['name'] as const)('gadget')
const notGadget = products.filter(not(matchGadget))
console.log(notGadget) // Filters products that are not gadgetsThe inclusive friend, or invites all possibilities to the party. Perfect for when you're not picky, it's the open-minded ally that plays well with matchesPluckedStrings, embracing a wide array of conditions with a welcoming grin.
import { or, matchesPluckedStrings } from 'fancy-collections'
const products = [
{
id: '123',
name: 'SuperWidget',
description: 'The ultimate widget',
details: { category: 'Widgets' },
},
{
id: '456',
name: 'MegaGadget',
description: 'A revolutionary gadget',
details: { category: 'Gadgets' },
},
]
const matchWidget = matchesPluckedStrings(['name'] as const)('widget')
const matchGadgetsCategory = matchesPluckedStrings([
'details.category',
] as const)('Gadgets')
const widgetOrGadgetsCategory = products.filter(
or(matchWidget, matchGadgetsCategory)
)
console.log(widgetOrGadgetsCategory) // Filters products that are either widgets or in the Gadgets categoryLike a bouncer at the club, isNotNull ensures that nulls don't crash your array's party. Post-filter, your array struts confidently, free of nulls and full of possibilities, typed with the assurance of a VIP list.
import { isNotNull } from 'fancy-collections'
const users: Array<{ name: string } | null> = [{ name: 'Alice' }, null]
const onlyUsers = users.filter(isNotNull)
console.log(onlyUsers) // Filters out null, array is typed without nullThe meticulous librarian, isNotUndefined sifts through your array with a discerning eye, removing any undefined elements. What remains is a well-curated collection, typed and tidy, like books neatly arranged on a shelf.
import { isNotUndefined } from 'fancy-collections'
const usersWithUndefined: Array<{ name: string } | undefined> = [
{ name: 'Bob' },
undefined,
]
const definedUsers = usersWithUndefined.filter(isNotUndefined)
console.log(definedUsers) // Filters out undefined, array is typed without undefinedTo run tests, run the following command
npm run testOr to run typing tests
npm run typing-testsGot an idea to make fancy-collections even more awesome? Don't hesitate to contribute. Contributions are always welcome.
Created with ❤️ by @avfirsov with assistance of ChatGPT and Pieces For Developers (tests, description and readme)