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Async Railway Oriented Programming in JS
#!/bin/env node
//thx to http://fsprojects.github.io/Chessie/a-tale-of-3-nightclubs.html
Promise.all([
suitablePersonEnterGayBar(),
unsuitablePersonEnterGayBar(),
])
.then(result => result.map((person, i) => `Person ${i+1}: ${person.cost || ''}${person.reasons.join(' ')}`))
.then(result => console.log(`Person entries\n${result.join('\n')}`));
module. exports = () => {
return {
Person: Person,
enterGayBar: enterGayBar,
costToEnter: costToEnter,
checkClothes: checkClothes,
checkAge: checkAge,
checkGender: checkGender,
};
};
function suitablePersonEnterGayBar() {
return enterGayBar(new Person('Male', 24, ['Shirt']));
}
function unsuitablePersonEnterGayBar() {
return enterGayBar(new Person('Male', 17, ['Tie']));
}
function Person (gender, age, clothes, sobriety) {
this.gender = gender;
this.age = age;
this.clothes = clothes || [];
this.sobriety = sobriety
}
function enterGayBar (person) {
return costToEnter(person, [checkGender, checkAge, checkClothes])
.then(data => ({cost: data, reasons: []}))
.catch(err => ({reasons: err}));
}
function costToEnter (person, rules) {
const initial = {
failures: [],
success: person.gender === 'Female' ? 0 : 5,
};
return Promise
.all(rules.map(fn => fn(person).catch(err => err)))
.then(results => {
const result = results.reduce((state, result) => {
if(result.message) state.failures.push(result.message);
return state;
}, initial);
if(result.failures.length > 0) return Promise.reject(result.failures);
return Promise.resolve(result.success);
});
}
function checkClothes (person) {
if(person.gender === 'Male' && person.clothes.indexOf('Tie') !== -1) return Promise.reject(new Error('Smarten up!'));
if(person.gender === 'Female' && person.clothes.indexOf('Trainers') !== -1) return Promise.reject(new Error('Smarten up!'));
return Promise.resolve(person);
}
function checkAge (person) {
if(person.age < 18) return Promise.reject(new Error('Too young!'));
if(person.age > 40) return Promise.reject(new Error('Too old!'));
return Promise.resolve(person);
}
function checkGender (person) {
if(person.gender === 'Female') return Promise.reject(new Error('Men only!'));
return Promise.resolve(person);
}
const assert = require('assert');
const asyncEitherExample = require('./async-either-with-promise')();
describe('Async either with promises', () => {
it('person (Male, 24, Shirt) should suitable', () => {
const person = new asyncEitherExample.Person('Male', 24, ['Shirt']);
return asyncEitherExample
.enterGayBar(person)
.then(actual => {
assert.equal(actual.cost, 5);
});
});
it('person (Male, 17, Tie) should unsuitable', () => {
const person = new asyncEitherExample.Person('Male', 17, ['Tie']);
return asyncEitherExample
.enterGayBar(person)
.then(actual => {
assert.deepEqual(actual.reasons, ['Too young!', 'Smarten up!']);
});
});
it('person (Female, 25, Trainers) should unsuitable', () => {
const person = new asyncEitherExample.Person('Female', 25, ['Trainers']);
return asyncEitherExample
.enterGayBar(person)
.then(actual => {
assert.deepEqual(actual.reasons, ['Men only!', 'Smarten up!']);
});
});
it('person (Male, 41) should unsuitable', () => {
const person = new asyncEitherExample.Person('Male', 41);
return asyncEitherExample
.enterGayBar(person)
.then(actual => {
assert.deepEqual(actual.reasons, ['Too old!']);
});
});
});
@GregOnNet

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commented Feb 22, 2017

👍

@MikeBild

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Owner Author

commented Feb 25, 2017

updated ;-)

@stainful

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commented Nov 10, 2018

👍

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