2

When I create a nested array, say: 

let x = [[0, 1], 2, [3, [4, 5]]];

and convert it to a string with .toString():

x.toString();
-> "0,1,2,3,4,5"

It doesn't preserve the nested structure of the array. I would like to get something like:

x.toString();
-> "[0,1],2,[3,[4,5]]"

Is there any smarter way of doing this other than looping through elements of x, testing if an element is an array etc.?

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3
  • 3
    Have you tried JSON.stringify(x)? Commented Sep 1, 2019 at 3:35
  • I hadn't thought about using stringify, and then I could just substring out the first and last brackets... Commented Sep 1, 2019 at 3:39
  • 1
    JSON.stringify(x).slice(1, -1) Commented Sep 1, 2019 at 5:17

2 Answers 2

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3

You can use JSON.stringify and replace

 ^\[|\]$

enter image description here

let x = [[0, 1], 2, [3, [4, 5]]]; 

let final = JSON.stringify(x)

// with regex
console.log(final.replace(/^\[|\]$/g,''))

// without regex
console.log(final.slice(1, -1))

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4 Comments

Or just do a substring via slice?
I'll accept this in a minute when it will let me :)
I hadn't thought about using regex, I was just going to substring or slice like @Li357 commented. That's an interesting approach.
@Li357 yeah fair thing to do, add that too :)
1

Or possibly use a generator to build up a string manually:

 function* asNested(array) {
    for(const el of array)
      if(Array.isArray(el)) {
         yield "[";
         yield* asNested(el);
          yield "]";
      } else yield el.toString();
 }

 const result = [...asNested([[1, 2], [3, 4]])].join("");
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2 Comments

This seems unnecessarily complicated compared to the above approach, and seems like it would use more time and computer resources, this is essentially the approach is said I wouldn't like in my question.
More complicated, yes, not necessarily slower.

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