Lodash uniqBy调用的Ramda等效项是什么？

Question

const data = [
{id: "001", failedReason: [1000]},
{id: "001", failedReason: [1001]},
{id: "001", failedReason: [1002]},
{id: "001", failedReason: [1000]},
{id: "001", failedReason: [1000, 1003]},
{id: "002", failedReason: [1000]}
];

Given this data set if I wanted to return an array of objects with unique id values only then I could use Lodash to simply call: _.uniqBy(data, 'id')

I know that with this method only the first occurrence of an element/match is kept.

The above would return:

[ { id: '001', failedReason: [ 1000 ] },
  { id: '002', failedReason: [ 1000 ] } ]

I'm brand new to Ramda. What is the Ramda one- liner equivalent to this?

R.uniqBy(???, data)

Answer 1

Just return the id of each element:

 const data = [ {id: "001", failedReason: [1000]}, {id: "001", failedReason: [1001]}, {id: "001", failedReason: [1002]}, {id: "001", failedReason: [1000]}, {id: "001", failedReason: [1000, 1003]}, {id: "002", failedReason: [1000]} ]; const res = R.uniqBy(({ id }) => id, data); console.log(res); 

 .as-console-wrapper { max-height: 100% !important; top: auto; } 

 <script src="//cdnjs.cloudflare.com/ajax/libs/ramda/0.25.0/ramda.min.js"></script> 

You could also use the Ramda prop function:

 const data = [ {id: "001", failedReason: [1000]}, {id: "001", failedReason: [1001]}, {id: "001", failedReason: [1002]}, {id: "001", failedReason: [1000]}, {id: "001", failedReason: [1000, 1003]}, {id: "002", failedReason: [1000]} ]; const res = R.uniqBy(R.prop("id"), data); console.log(res); 

 .as-console-wrapper { max-height: 100% !important; top: auto; } 

 <script src="//cdnjs.cloudflare.com/ajax/libs/ramda/0.25.0/ramda.min.js"></script> 

Answer 2

Ramda doesn't do the lodash style of allowing a string to serve as an alternative for a function to get the named property of an object. So just pass a function:

 const data = [ {id: "001", failedReason: [1000]}, {id: "001", failedReason: [1001]}, {id: "001", failedReason: [1002]}, {id: "001", failedReason: [1000]}, {id: "001", failedReason: [1000, 1003]}, {id: "002", failedReason: [1000]} ]; console.log(uniqBy(prop('id'), data)) 

 <script src="https://bundle.run/ramda@0.26.1"></script><script> const {uniqBy, prop} = ramda </script>