CODEWITHSUNDEEP
javascriptramda.js
Vadim Svetlov
Vadim Svetlov

Reputation: 11

Some in Ramda.js

I'm trying to do a something like .some in js, but with ramda.js. And I can't understand how. I have an array of objects, and I want to get a true/false if some of object has value property with array.length > 1.

const features = [
{
    name: "First name",
    type: "First type",
    value: ["First value 1", "First value 2"],
},
{
    name: "Second name",
    type: "Second type",
    value: ["Second value 1"],
}
];

In vanilla.js it can be like:

features.some((f) => f.value.length > 1)

But I want to do it with Ramda. And try this, but it is not work:

const isHasSomeValues = R.gt(R.length(R.prop('value')), 1);
console.log(R.any(isHasSomeValues)(features))

Upvotes: 1

Views: 1286

Answers (2)

Ori Drori
Ori Drori

Reputation: 193348

R.any excepts a predicate function, and isHasSomeValues is actually a false value:

const isHasSomeValues = R.gt(R.length(R.prop('value')), 1);

console.log(isHasSomeValues);
<script src="https://cdnjs.cloudflare.com/ajax/libs/ramda/0.27.1/ramda.js" integrity="sha512-3sdB9mAxNh2MIo6YkY05uY1qjkywAlDfCf5u1cSotv6k9CZUSyHVf4BJSpTYgla+YHLaHG8LUpqV7MHctlYzlw==" crossorigin="anonymous"></script>

To create a function that is a combination of multiple functions you can use R.pipe or R.compose to perform a set of actions, where each action receives the result of the previous one. The first action (function) in the pipeline is called with the values passed into the pipe - an object in your case.

const { pipe, any, prop, length, gt, __ } = R

const fn = any(pipe(
  prop('value'), // get the value array
  length, // get the length
  gt(__, 0), // check if the length is greater than 0
))

const features = [{"name":"First name","type":"First type","value":["First value 1","First value 2"]},{"name":"Second name","type":"Second type","value":["Second value 1"]}]

const result = fn(features)

console.log(result)
<script src="https://cdnjs.cloudflare.com/ajax/libs/ramda/0.27.1/ramda.js" integrity="sha512-3sdB9mAxNh2MIo6YkY05uY1qjkywAlDfCf5u1cSotv6k9CZUSyHVf4BJSpTYgla+YHLaHG8LUpqV7MHctlYzlw==" crossorigin="anonymous"></script>

There are other ways to combine functions in Ramda, one of them is currying. All of Ramda's functions are curried, and all of them has a fixed arity (the number of parameters the function accepts). This means that if pass a single parameter to a function that requires 2, you'll get back a partially applied function. Only when you'll supply a 2nd parameter, the function would return the result.

In this case, R.any has an arity of 2. I pass it the predicate (pipe(...)), and get a new function. Only when I supply the 2nd value (the array), I get the result.

Upvotes: 2

Hitmands
Hitmands

Reputation: 14199

I'd probably approach this like is the prop value not empty?, as you are not really interested in how many items the value contains... gt 0 is enough.

const isValueEmpty = R.propSatisfies(R.isEmpty, 'value');

const fn = R.any(
  R.complement(isValueEmpty),
);

const data = [
  {
    name: 'First name',
    type: 'First type',
    value: ['First value 1', 'First value 2'],
  },
  {
    name: 'Second name',
    type: 'Second type',
    value: ['Second value 1'],
  },
];

console.log(
  fn(data),
);
<script src="https://cdnjs.cloudflare.com/ajax/libs/ramda/0.27.1/ramda.js" integrity="sha512-3sdB9mAxNh2MIo6YkY05uY1qjkywAlDfCf5u1cSotv6k9CZUSyHVf4BJSpTYgla+YHLaHG8LUpqV7MHctlYzlw==" crossorigin="anonymous"></script>

Upvotes: 3

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