Edit each value of an array of objects based on key

Question

Suppose I have two arrays like these:

const dataset = [{n: "2", s: 'hello', b: 'TRUE'}, {n: "0", s: 'meow', b: 'FALSE'}]
const info = {n:{type: 'TEXT'}, s:{type: 'PARAGRAPH'}, b:{type: 'CHECKBOX'}}

and I want to transform dataset in this:

const dataset = [{n: 2, s: 'hello', b: true}, {n: 0, s: 'meow', b: false}]

so values with key n become numbers, values with key s became stringa and values with key b became booleans.

So I created this function to match info type and the key:

function dataType(formType) {
  switch (formType) {
    case 'TEXT':
      return 'number'
    case 'PARAGRAPH':
      return 'string'
    case 'CHECKBOX':
      return 'boolean'
    default:
      throw new Error(`Something went wrong.`)
  }
}

Now I need a function that parse dataset, check each object and transform all the values. I prefer to make a copy of dataset, so immutability.

I think to use a reduce but I need help:

function dataParse(dataset, info) {
  const result = dataset.map((datum) => {
    return Object.entries(datum).reduce((acc, curr, i) => {
      // ???
      return acc
    }, {})
  })
  return result
}

I suppose to use a code similar to:

let v // don't like let
switch (value) {
          case 'number':
            v = +response
            break
          case 'string':
            v = response.toString()
            break
          case 'boolean':
            v = v === 'TRUE' ? true : false
            break
          default:
            throw new Error(`Something went wrong.`)

but how?

The complete code is here:

function dataType(formType) {
  switch (formType) {
    case 'TEXT':
      return 'number'
    case 'PARAGRAPH':
      return 'string'
    case 'CHECKBOX':
      return 'boolean'
    default:
      throw new Error(`Something went wrong.`)
  }
}

function dataParse(dataset, info) {
  const result = dataset.map((datum) => {
    return Object.entries(datum).reduce((acc, curr, i) => {
      // ???
      return acc
    }, {})
  })
  return result
}

const dataset = [{n: "2", s: 'hello', b: 'TRUE'}, {n: "0", s: 'meow', b: 'FALSE'}]
const info = {n:{type: 'TEXT'}, s:{type: 'PARAGRAPH'}, b:{type: 'CHECKBOX'}}

console.log(dataParse(dataset, info))

Norse · Accepted Answer · 2021-04-08 09:44:36Z

1

I would just do a loop, and drop the info object like so

const dataset = [{n: "2", s: 'hello', b: 'TRUE'}, {n: "0", s: 'meow', b: 'FALSE'}]

const newDataset = dataset.map((data) => {
  return {n: parseInt(data.n), s: data.s, b: data.b === "TRUE" ? true : false}
})

console.log(newDataset)

or something similar. If you are sure that n always contains a number and b is always either "TRUE"or "FALSE", I think this is the way to go.

Otherwise, to continue on your example:

function transform(data, info) {
  let newObj = {};
  Object.keys(data).forEach((key) => {
    switch(info[key].type) {
      case 'TEXT':
        newObj[key] = parseInt(data[key])
        break;
      case 'PARAGRAPH':
        newObj[key] = data[key]
        break;
      case 'CHECKBOX':
        newObj[key] = data[key] === "TRUE" ? true : false;
        break;
      default:
        throw new Error(`Something went wrong.`)
    }
  })
  return newObj
}

function dataParse(dataset, info) {
  const result = dataset.map((datum) => {
    return transform(datum, info)
  })
  return result
}

const dataset = [{n: "2", s: 'hello', b: 'TRUE'}, {n: "0", s: 'meow', b: 'FALSE'}]
const info = {n:{type: 'TEXT'}, s:{type: 'PARAGRAPH'}, b:{type: 'CHECKBOX'}}

console.log(dataParse(dataset, info))

edited Apr 8, 2021 at 9:44

answered Apr 8, 2021 at 9:27

Norse

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1 Comment

marielle Over a year ago

Thank you, but it's not so simple. I have to use info object and dataType function

FZs · Accepted Answer · 2021-04-08 09:46:27Z

Your attempt is almost right.

It's also possible with Array#reduce(), but there's a relatively new method, Object.fromEntries(), that reverses Object.entries(), and makes your life easier:

function convert(value, formType) {
  switch (formType) {
    case 'TEXT':
      return Number(value) //Same as `+value`
    case 'PARAGRAPH':
      return String(value) //Better than `toString()`, works with all values
    case 'CHECKBOX':
      return value === 'TRUE' //No need for ternary here, `===` already returns a boolean!
    default:
      throw new Error(`Something went wrong.`)
  }
}

function dataParse(dataset, info){
  return dataset.map(obj => 
    Object.fromEntries(
      Object.entries(obj).map(([k, v]) => 
        [k, convert(v, info[k].type)]
      )
    )
  )
}

const dataset = [{n: "2", s: 'hello', b: 'TRUE'}, {n: "0", s: 'meow', b: 'FALSE'}]
const info = {n:{type: 'TEXT'}, s:{type: 'PARAGRAPH'}, b:{type: 'CHECKBOX'}}

console.log(dataParse(dataset, info))

If you have to use the dataType for handling types, you can change convert to accept the type returned by dataType instead:

function convert(value, formType) {
  switch (formType) {
    case 'number':
      return Number(value) //Same as `+value`
    case 'string':
      return String(value) //Better than `toString()`, works with all values
    case 'boolean':
      return value === 'TRUE' //No need for ternary here, `===` already returns a boolean!
    default:
      throw new Error(`Something went wrong.`)
  }
}

function dataType(formType) {
  switch (formType) {
    case 'TEXT':
      return 'number'
    case 'PARAGRAPH':
      return 'string'
    case 'CHECKBOX':
      return 'boolean'
    default:
      throw new Error(`Something went wrong.`)
  }
}

function dataParse(dataset, info){
  return dataset.map(obj => 
    Object.fromEntries(
      Object.entries(obj).map(([k, v]) => 
        [
          k, 
          convert(
            v, 
            dataType(info[k].type)
          )
        ]
      )
    )
  )
}

const dataset = [{n: "2", s: 'hello', b: 'TRUE'}, {n: "0", s: 'meow', b: 'FALSE'}]
const info = {n:{type: 'TEXT'}, s:{type: 'PARAGRAPH'}, b:{type: 'CHECKBOX'}}

console.log(dataParse(dataset, info))

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