How do I turn this array of objects into a string using ES6 methods?

Question

I have the following array of objects:

const pagesByBook = [
{bookName: "An old tome", pages: 123},
{bookName: "Really ancient stuff", pages: 432},
{bookName: "Yup, another old book", pages: 218}
]

And I would like to get the following string output:

        const output= "['An old tome', 123, 'old', null],
        ['Really ancient stuff', 432, 'old', null],
        ['Yup, another old book', 218, 'old', null]"

How can I do this using in a few lines using ES6 methods such as map?

Maybe. Have you tried anything? DId you get stuck somewhere? — Dexygen
– Dexygen, Commented Nov 11, 2018 at 18:37
@Bergi: I guess 'old' could be a constant. Regarding the weird string format, I don't know, because I need to output like a string. I don't know how I could do that with JSON. If it works the same then I'm ok with that possibility. — nicokruk
– nicokruk, Commented Nov 11, 2018 at 18:46

Akrion · Accepted Answer · 2018-11-11 22:38:12Z

1

This seems to me to be a simple map with ES6 destructuring. Assuming that the last 2 elements in the arrays are constants (old, null):

const data = [ {bookName: "An old tome", pages: 123}, {bookName: "Really ancient stuff", pages: 432}, {bookName: "Yup, another old book", pages: 218} ] 

const result = data.map(({bookName, pages}) => [bookName, pages, 'old', null])

console.log(JSON.stringify(result))

If a string representation of this is needed you could change it to:

const data = [ {bookName: "An old tome", pages: 123}, {bookName: "Really ancient stuff", pages: 432}, {bookName: "Yup, another old book", pages: 218} ] 

const result = data.map(({bookName, pages}) => JSON.stringify([bookName, pages, 'old', null]))

console.log(result.join(','))

edited Nov 11, 2018 at 22:38

answered Nov 11, 2018 at 22:31

Akrion

18.6k1 gold badge38 silver badges58 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

kemicofa · Accepted Answer · 2018-11-11 18:45:09Z

0

Use JSON.stringify, Array#map, Object.values, Array#slice and Array#concat to get your required result.

const pagesByBook = [{
    bookName: "An old tome",
    pages: 123
  },
  {
    bookName: "Really ancient stuff",
    pages: 432
  },
  {
    bookName: "Yup, another old book",
    pages: 218
  }
]

const res = JSON.stringify(pagesByBook.map(item => Object.values(item).concat("old", null))).slice(1, -1);

console.log(res)

answered Nov 11, 2018 at 18:45

kemicofa

17.7k10 gold badges93 silver badges145 bronze badges

Collectives™ on Stack Overflow

How do I turn this array of objects into a string using ES6 methods?

2 Answers 2

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related