使用ramda防止重复代码

Question

i have a list of same operation on same list using ramda like below :

 size: { sum: R.sum(R.map(R.prop('size'), ordersRep)) },
      price: { sum: R.sum(R.map(R.prop('price'), ordersRep)) },
      profit: { sum: R.sum(R.map(R.prop('profit'), ordersRep)) },
      discount: { sum: R.sum(R.map(R.prop('discount'), ordersRep)) },

which i want to define main function : R.sum(R.map(R.prop('somthing'), ordersRep)) other place and use it wheneve needed. but it's take two argument one list and one prop name. how can i handle it ?

Answer 1

let combined = (prop, coll) => R.sum(R.pluck(prop, coll))

For an arguably more functional version (point-free courtesy of Ross Mackay):

let combined = prop => R.compose(R.sum, R.pluck(prop))

let sumPrice = combined('price');
sumPrice([{price: 2}, {price: 3}]); // 5

Point-free:

let combined = R.curryN(2, R.compose(R.sum, R.pluck));