funks v1.3.1

funks

Asynchronous model builder in functional style.

API

lift

The function lift takes pure function which describes process of creating independent block of data. For example:

const getUser = service('users.get');
const selectGoods = service('goods.selectByUser');
const selectCategoies = service('categoies.select');

const getCategoryIds = sync(arr => arr.map(x => x.categoryId));

const userGoods = lift(userId => {
    const user = getUser(userId);
    const goods = selectGoods(userId);
    const categoryIds = getCategoryIds(goods);
    const categories = selectCategoies(categoryIds);

    return {user, goods, categories};
});

All nondeterministic functions should be wrapped in sync function. For example:

const getStatsUntil = service('stats.getUntil');

const someStats = lift(() => {
    // In this instance "now" will be captured once,
    // and for every call of "someStats" function getStatsUntil would get the same date.
    const now = new Date();
    return getStatsUntil(now);
});

const someStats2 = lift(() => {
    // In this instance "now" will be calculated for every call of "someStats2"
    const now = sync(() => new Date());
    return getStatsUntil(now);
});

service

service :: key -> *... -> ServiceCall a

Service is a curried function, that takes key and arguments and after that returns object, which contains information about particular service call.

sync

sync :: (*... -> a) -> *... -> Sync a

Sync is a curried function, that firstly takes synchronous function then takes arguments and returns object, which describes non async computation.

or

or :: (pred, result) -> Or

Or is a function that takes predicate and result, which would be returned if predicate would be true, and returns object Or that can chain multiple conditions with results. In the end of the chain default value may be declared. If default value isn't decalred result would be undefined.

Examples:

const balloon =
    or(isRed, redBalloon(size))
    .or(isBlue, blueBalloon(size))
    .def(whiteBalloon(size));

// White balloon will be returned only if conditions "isRed" and "isBlue" will be false.

const valueOrUndefined = or(exists, create());

ext

ext :: (*... -> NotPromise a) -> *... -> Ext a

Takes function which doesn't return promise and should calculated with alternative way. For example if you use coroutines based on generators.

const genEcho = function *(value) {
    yield 'simulating calculation';
    return value;
};

const extEcho = ext(genEcho);

lift(value => {
    const result = extEcho(value);
    return sync(r => `Server respond: ${r}`)(result);
});

External handlers should be added using function registerExt. For example:

const {registerExt} = require('funks').plan;
const co = require('co');

const genConstructor = (function *() {})().constructor;

const coHandle = value => co(value);
const coCanHandle = value => value && value.constructor === genConstructor;

registerExt(coCanHandle, coHandle);