Created
October 25, 2017 02:17
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const Future = require('fluture'); | |
const R = require('ramda'); | |
const {Reader} = require('monet'); | |
const FakeDb = () => { | |
const data = { | |
1: {id: 1, name: 'bob', bff: 2}, | |
2: {id: 2, name: 'alice', bff: 1} | |
}; | |
return { byId: id => Promise.resolve(data[id]) }; | |
}; | |
const upperName = data => data.name.toUpperCase(); | |
const getUser1 = Reader(db => db.byId(1)); | |
const getBestFriend = data => Reader(db => db.byId(data.bff)); | |
const ReaderPromise = value => { | |
const map = fn => ReaderPromise( | |
value.map( | |
promise => promise.then(fn) | |
) | |
); | |
const chain = fn => ReaderPromise( | |
value.chain( | |
promise => Reader( | |
config => promise.then( | |
(...args) => fn(...args).run(config) | |
) | |
) | |
) | |
); | |
return Object.freeze({chain, map, run: (config) => value.run(config)}); | |
} | |
const program = ReaderPromise(getUser1) | |
.chain(data => ReaderPromise(getBestFriend(data))) | |
.map(upperName) | |
program.run(FakeDb()).then(console.log); |
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