Using Promise.all inside a Ramda pipe

Question

How is Promise.all used in a ramda pipe? I think I'm missing something silly here.

const pipeline: Function = R.pipe(
    R.map((record) => record.body),
    R.map(JSON.parse),
    R.map(asyncFunction),
    console.log
);

Returns an array of promises (the input to Promise.all)

[ Promise { <pending> },
  Promise { <pending> },
  Promise { <pending> },
  Promise { <pending> },
  Promise { <pending> },
  Promise { <pending> },
  Promise { <pending> },
  Promise { <pending> },
  Promise { <pending> },
  Promise { <pending> } ]

However if I try to wait for those promises to resolve with Promise.all, like so:

const pipeline: Function = R.pipe(
    R.map((record) => record.body),
    R.map(JSON.parse),
    R.map(asyncFunction),
    Promise.all,
    R.andThen(useTheReturn)
);

I end up with a type error stating that i'm trying to use Promise.all as a constructor type.

{
    "errorType": "TypeError",
    "errorMessage": "#<Object> is not a constructor",
    "stack": [
        "TypeError: #<Object> is not a constructor",
        "    at all (<anonymous>)",
        "    at /var/task/node_modules/ramda/src/internal/_pipe.js:3:14",
        "    at /var/task/node_modules/ramda/src/internal/_arity.js:11:19",
        "    at Runtime.exports.handler (/var/task/lambda/data-pipeline/1-call-summary-ingestion/index.js:14:19)",
        "    at Runtime.handleOnce (/var/runtime/Runtime.js:66:25)"
    ]
}

Answer 1

You'll need to bind Promise.all to Promise:

const pipeline: Function = R.pipe(
  R.map((record) => record.body),
  R.map(JSON.parse),
  R.map(asyncFunction),
  R.bind(Promise.all, Promise),
  R.andThen(useTheReturn)
);

Demo:

const pipeline = R.pipe(
  R.bind(Promise.all, Promise),
  R.andThen(R.sum)
);

const promise1 = Promise.resolve(10)
const promise2 = 20
const promise3 = new Promise((resolve) => setTimeout(resolve, 100, 30))

const result = pipeline([promise1, promise2, promise3])

result.then(console.log)

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