♻️ Lazily collect and query generators in JS
⚠️ This project is experimental and should not be considered stable for production use.
- Collect and query generator results using coroutines
- Iterate only to the values you need, only when you need them
- Seamless integration with promises and async functions
- 📖 Documentation
- ⚓ Install
- 🔧 API
- 💡 Usage and Examples
The following node example uses generator-collector and js-coroutines to query for the 5 best red wines in France.
import { collector, promiser, each } from 'generator-collector'
import { map, sort } from 'js-coroutines' // optional, but plays nice with other coroutine libraries
async function wine () {
const categories = ['reds', 'whites', 'sparkling', 'rose', 'dessert', 'port']
// Create a generator-based "promiser" (coroutine) that loads and sorts a list of wines within a category
const api = promiser(function* (category = 'reds') {
const response = yield fetch(`https://api.sampleapis.com/wines/${category}`)
const data = yield response.json()
const rated = yield* sort(data, function* (a, b) {
return yield b.rating.average - a.rating.average
})
const items = yield* map(rated, function* (item) {
return yield { ...item, category }
})
return items
})
// Create a collector that reduces each result from the queried API responses into a single collection
const load = collector(function* (query = null) {
yield* each(query ?? categories, api)
}, {
// Override default insert behavior of `push.call` (now `push.apply`).
// Enables flat reduction of each item in the API responses ([a, b, c] vs. [[a], [b], [c]]).
insert: (store, value) => Array.prototype.push.apply(store, value)
})
// Invoke our data fetching collector for red wines (call `load()` instead for all wine categories)
const query = load(['reds'])
// Load all the red wines from the API (since we need the full list to know the "best")
const all = await query.all()
// Scan results for the top 5 best red wines from France
const best = await query.take(5, (item) => item.location.startsWith('France'), true)
return { all, best }
}
wine().then(result => {
console.log('Loaded best red wines in France', result.best, result.all.length)
process.exit(0)
})- Create a GitHub issue for bug reports, feature requests, or questions
- Add a ⭐️ star on GitHub or ❤️ tweet to support the project!
Copyright © Erik Vavro. All rights reserved.
Licensed under the MIT License.