rm-infinity
v0.0.9
Published
Sorted data from multiple paginated sources
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rm-infinity
Get combined sorted data from multiple paginated data sources
it works by getting data from paginated sources and work out which elements that can be combined into one single response based on where the different results intersect.
Install
npm i rm-infinity
API docs
https://redmindab.github.io/rm-infinity/
Usage
Given this dataset
const cats: Cat[] = [
{
age: 9,
name: 'Whiskers',
},
{
age: 6,
name: 'Tigger',
},
{
age: 3,
name: 'Sassy',
},
{
age: 1,
name: 'Simba',
},
];
const dogs: Dog[] = [
{
birthDate: '2012-01-01',
name: 'Shadow',
},
{
birthDate: '2013-05-21',
name: 'Lucky',
},
{
birthDate: '2014-01-01',
name: 'Sam',
},
{
birthDate: '2015-01-01',
name: 'Buddy',
},
{
birthDate: '2019-01-01',
name: 'Molly',
},
];
- We want to get all the cats and dogs in a stream like manner
- sorted by the age of the animal with the oldest first.
to achive this with rm-infinity we just create a InfinityEngine
with a ascending configuration (if we convert age and birthdate to unix time)
import { InfinityEngine, InfinityConfig } from 'rm-infinity';
// Accending because timestamps from oldest to newest are ascending.
const Engine = new InfinityEngine({ ascending: true });
Then we create a configuration to query the datasets
const config = [
{
name: 'cats',
offset: 0, // original offset is 0
query: (offset) => Promise.resolve(cats.slice(offset, 3 + offset)), // getting 3 results per page
sortValue: (cat) => moment().subtract(cat.age, 'years').unix(),
} as InfinityConfig<Cat>,
{
name: 'dogs',
offset: 0, // original offset is 0
query: (offset) => Promise.resolve(dogs.slice(offset, 2 + offset)), // Getting 2 results per page
sortValue: (dog) => moment(dog.birthDate).unix(),
} as InfinityConfig<Dog>,
];
pass the configuration to the engine
const result = await Engine.getNext(config);
/*
{ data:
[ { age: 9, name: 'Whiskers' },
{ birthDate: '2012-01-01', name: 'Shadow' },
{ birthDate: '2013-05-21', name: 'Lucky' } ],
newOffsets: [ { name: 'cats', value: 1 }, { name: 'dogs', value: 2 } ] }
*/
How it works
if this is the data returned by the queries
const arr1 = [5, 4, 3, 2, 1];
const arr2 = [7, 5, 0];
The engine will first find the max value comparing arr1[0]
and arr2[0]
which in this case is 7
then find the max value for arr1[arr1.length - 1]
and arr2[arr2.length - 1]
which is 1
after that it will combine and sort all results in decending order.
{
data: [7, 5, 5, 4, 3, 2, 1],
newOffsets: [
{
name: 'arr1',
offset: 5,
},
{
name: 'arr2',
offset: 2,
},
],
}