Ramda.js通过对象值创建过滤器函数

Question

I'm learning FP and trying to figure this out:

I have a list of users and need to create a function to filter them by name. That's what I tried:

let users = [{name: "rod"}]

let nameEq = R.prop("name")

let filterByName = R.compose( 
  R.filter(R._, users),
  nameEq
);

filterByName("rod")

This doesn't work because filter returns an array. I guess I need to curry filter some way, but can't figure it out.

Answer 1

If you are looking for a point free sort of style, how about this approach:

const R = require('ramda');

// sample data
const data = [{name: 'rod', age: 25}, {name: 'chuck', age: 30}, {name: 'rod', age: 50}];


// Alternative 1: bake in the name and vary the data

const filterByName = R.compose(R.filter, R.propEq('name'));

const filterByRod = filterByName('rod');

// now supply the data
filterByRod(data); // => [ { name: 'rod', age: 25 }, { name: 'rod', age: 50 } ]


// Alternative 2: bake in the data, and then vary the name

const filterDataByName = R.compose(R.partialRight(R.filter, [data]), R.propEq('name'));

// now supply the name
filterDataByName('rod'); // => [ { name: 'rod', age: 25 }, { name: 'rod', age: 50 } ]

Believe you were aiming to do Alternative 2 above in your question.