CODEWITHSUNDEEP
ramda.js
Rio
Rio

Reputation: 123

Unable to catch arguments in "R.applySpec" : Ramda.js

I am basically trying to achieve the code below within the R.applySpec.

const fn = ({target, count}) => R.unnest (R.zipWith (R.repeat) (target, count))

const Data = { 
  target : ["a", "b", "c"], 
  count : [1, 2, 3],
}

const data1= {
  result : fn (Data)
}
console.log ( 'data1:', data1.result);// ["a","b","b","c","c","c"]

What I cannot figure out is that arguments in the fn seems to be uncaught within the R.applySpec

const data2_applySpec = R.applySpec({
  result : R.lift ( R.zipWith ( fn )) ( R.prop ('target'),  R.prop ('count'))
})

const data2 = data2_applySpec(Data)
console.log ('data2:', data2);//ERROR

How can I alter the fn to make it work? I use Ramda.js. Thanks.

REPL

Upvotes: 0

Views: 85

Answers (2)

Scott Sauyet
Scott Sauyet

Reputation: 50787

I think you're making this harder than it needs to be.

You already have the function you want to use inside applySpec stored as fn.

So you can just write:

const fn2 = applySpec ({
  result: fn
})

Or, if your only use of fn is inside this applySpec call, then just inline it:

const fn3 = applySpec ({
  result: ({target, count}) => unnest (zipWith (repeat) (target, count))
})

And if you have a fetish for point-free code, you can use the technique discussed in your earlier post:

const fn4 = applySpec ({
  result: compose (unnest, apply (zipWith (repeat)), props (['target', 'count']))
})

(or the similar version from Ori Drori.)

All of these are shown in this snippet.

const fn1 = ({target, count}) => unnest (zipWith (repeat) (target, count))

const fn2 = applySpec ({
  result: fn1
})

const fn3 = applySpec ({
  result: ({target, count}) => unnest (zipWith (repeat) (target, count))
})

const fn4 = applySpec ({
  result: compose (unnest, apply (zipWith (repeat)), props (['target', 'count']))
})


const data = {target : ["a", "b", "c"], count : [1, 2, 3]}

console .log (fn1 (data))
console .log (fn2 (data))
console .log (fn3 (data))
console .log (fn4 (data))
.as-console-wrapper {max-height: 100% !important; top: 0}
<script src="//cdnjs.cloudflare.com/ajax/libs/ramda/0.27.1/ramda.min.js"></script>
<script> const {unnest, zipWith, repeat, applySpec, compose, apply, props} = R </script>

Upvotes: 1

Ori Drori
Ori Drori

Reputation: 191976

You can can an array of arrays ([target, count]) using R.props, apply the array of array to R.zipWith(repeat), and then flatten the results with R.unnest:

const { applySpec, pipe, props, apply, zipWith, repeat, unnest } = R

const Data = { 
  target : ["a", "b", "c"], 
  count : [1, 2, 3],
}

const data2_applySpec = applySpec({
  result: pipe(props(['target', 'count']), apply(zipWith(repeat)), unnest)
})

const result = data2_applySpec(Data)

console.log(result)
<script src="https://cdnjs.cloudflare.com/ajax/libs/ramda/0.27.1/ramda.min.js" integrity="sha512-rZHvUXcc1zWKsxm7rJ8lVQuIr1oOmm7cShlvpV0gWf0RvbcJN6x96al/Rp2L2BI4a4ZkT2/YfVe/8YvB2UHzQw==" crossorigin="anonymous"></script>

Upvotes: 2

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