CODEWITHSUNDEEP
javascriptfunctional-programming
defraggled
defraggled

Reputation: 1218

Best functional-style syntax to build this object?

The below code achieves desired output. Is there a more elegant way to do this?

For example, is there some native javascript function like flatMap etc that would help?

(I know I could get rid of the intermediate variable pieces).

const config = {
    fieldName1: {
        validation: "schema1",
        value: "abcvalue here"
    },
    fieldName2: {
        validation: "schema2",
        value: "abcvalue here"
    },
}

// Desired output: 
// {
//     fieldName1: "schema1",
//     fieldName2: "schema2",
//     ...
// }
const extractValidation = (config) => {
    const pieces = Object.entries(config).map(
        ([key, val]) => ({
            [key]: val.validation
        })
    )
    return Object.assign({}, ...pieces)
}


extractValidation(config)

Upvotes: 4

Views: 79

Answers (3)

Hitmands
Hitmands

Reputation: 14199

this is how I would do it. By leveraging Ramda, you can go point-free and use map to any Functor

const fn = R.map(R.prop('validation'));

const data = {
  fieldName1: {
    validation: "schema1",
    value: "abcvalue here"
  },
  fieldName2: {
    validation: "schema2",
    value: "abcvalue here"
  },
};

console.log(
  fn(data),
);
<script src="https://cdnjs.cloudflare.com/ajax/libs/ramda/0.28.0/ramda.js" integrity="sha512-ZZcBsXW4OcbCTfDlXbzGCamH1cANkg6EfZAN2ukOl7s5q8skbB+WndmAqFT8fuMzeuHkceqd5UbIDn7fcqJFgg==" crossorigin="anonymous" referrerpolicy="no-referrer"></script>

Upvotes: 1

customcommander
customcommander

Reputation: 18941

An alternative is to use reduce so you can skip the Object.assign:

Object.entries(config).reduce((o, [k, v]) => (o[k] = v.validation, o), {})
//=> {fieldName1: 'schema1', fieldName2: 'schema2'}

Upvotes: 0

danh
danh

Reputation: 62676

It's more concise, and I think prettier, to pair fromEntries with a map over .entries.

const config = {
    fieldName1: {
        validation: "schema1",
        value: "abcvalue here"
    },
    fieldName2: {
        validation: "schema2",
        value: "abcvalue here"
    },
}

const extractValidation = (config) => Object.fromEntries(
  Object.entries(config).map(([k,v]) => [k, v.validation])
);

console.log(extractValidation(config))

Upvotes: 2

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