How to use the composeP function from ramda

Find comprehensive JavaScript ramda.composeP code examples handpicked from public code repositorys.

ramda.composeP is a function that composes a series of Promise-returning functions together, with the output of each function being passed as the input of the next.

API.md?plain=1

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const endpoint = req =>
  json({ isString: typeof req.body === 'string' })

const app =
  composeP(endpoint, bufferBody)

http.createServer(mount({ app })).listen(3000)
```

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+ 13 other calls in file

compose-result.js

GitHub: mvp-rockets/lib-core

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const init = Array.prototype.slice.call(arguments);
const last = init.pop();
return ifElse(
	R.isEmpty,
	() => R.composeP(last),
	() => R.composeP(
		R.composeP.apply(this, R.map(executeIfResultIsSuccessful, init)),
		last
	)
)(init);

How does ramda.composeP work?

ramda.composeP is a function that takes a list of functions that return promises, and returns a new function that applies those functions from right to left, with the output of each function becoming the input of the next, and returns a new promise that resolves to the final output of the composition.

dataSetup.js

GitHub: mvp-rockets/backend-core

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        return [data, entity];
    };
};


const buildSingle = function (entity, value) {
    return R.composeP(getEntity, R.head, addToCache, build(entity, value))();
};




const createAssociatedEntities = R.curry(

+ 2 other calls in file

cyclejs-audio-driver.js

GitHub: jemmyw/cyclejs-audio-driver

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* @since v0.10.0
* @category Function
* @sig ((a -> Promise b), (b -> Promise c), ..., (y -> Promise z)) -> (a -> Promise z)
* @param {...Function} functions
* @return {Function}
* @see R.composeP
* @example
*
*      //  followersForUser :: String -> Promise [User]
*      var followersForUser = R.pipeP(db.getUserById, db.getFollowers);

+ 35 other calls in file

Ai Example

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const R = require("ramda");

const multiplyAsync = async (x, y) => {
  return x * y;
};

const squareAsync = async (x) => {
  return x * x;
};

const divideAsync = async (x, y) => {
  return x / y;
};

const operations = R.composeP(squareAsync, multiplyAsync, divideAsync);

operations(4, 2)
  .then((result) => {
    console.log(result); // 4
  })
  .catch((error) => {
    console.error(error);
  });

In this example, we have three asynchronous functions: multiplyAsync, squareAsync, and divideAsync. We want to create a new function, operations, that performs these three functions in sequence. ramda.composeP is used to create this function. ramda.composeP returns a new function that takes the same arguments as the last function in the composition, in this case divideAsync. The returned function first calls divideAsync, then passes its result to multiplyAsync, and finally passes the result of multiplyAsync to squareAsync. The result of squareAsync is then returned by the composed function. In the example, operations(4, 2) returns a promise that resolves to 4, which is the result of squareAsync(multiplyAsync(divideAsync(4, 2))).

candidate.js

GitHub: SwapnilGoad/ServerlessDemo

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var body = JSON.parse(event.body);

const candidate = candidateInfo(body.fullname, body.email, body.experience);  

const candidateSubmissionFx = R.composeP(submitCandidateEmailP,submitCandidateP, checkCandidateExistsP);

candidateSubmissionFx(candidate)
.then(res => {
    console.log(`Successfully submitted ${body.fullname}(${event.email}) candidate to system`);

window.js

GitHub: lewisp6/tfl-status-bar

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  tubeStatuses.forEach((tubeLine) => {
    domWriter.writeDom(tubeLine.id, tubeLine.lineStatuses[0]['statusSeverityDescription']);
  });
}


const writeStatusesToDom = R.composeP(setTubeStatuses, status.getStatuses);


document.addEventListener('DOMContentLoaded', function() {
  writeStatusesToDom();
});

compose-result.js

GitHub: shawankit/TIMWM

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    }
    const init = Array.prototype.slice.call(arguments);
    const last = init.pop();
    return ifElse(R.isEmpty,
        () => R.composeP(last),
        () => R.composeP(R.composeP.apply(this, R.map(executeIfResultIsSuccessful, init)), last))(init);
};


const executeIfResultIsSuccessful = R.curry(async (fn, result) => {
    if (Result.hasInstance(result)) {

bundle.js

GitHub: Gaoey/canvas-vertice-google-detected-text

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*      const lookupUser = (userId) => Promise.resolve(db.users[userId])
*      const lookupFollowers = (user) => Promise.resolve(user.followers)
*      lookupUser('JOE').then(lookupFollowers)
*
*      //  followersForUser :: String -> Promise [UserId]
*      const followersForUser = R.composeP(lookupFollowers, lookupUser);
*      followersForUser('JOE').then(followers => console.log('Followers:', followers))
*      // Followers: ["STEVE","SUZY"]
*/

+ 7 other calls in file

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