How to convert a converted string back into an array?

Question

As far as I know, you can only save strings to local storage. So, I had to write a function so that I could save arrays. If I call console.log(fixA(["string1", [5, [false]], "string2"])); I get an output of "'string1',[5,[false]],'string2'". Here it is:

function fixA(array) {
  var toreturn = "";
  for (var i = 0; i < array.length; i++) {
    if (typeof array[i] === 'object') {
      toreturn += "[" + fixA(array[i]) + "]";
    } else {
      if (typeof array[i] === 'string') {
        toreturn += "'" + array[i] + "'";
      } else {
        toreturn += array[i];
      }
    }
    if (i < array.length - 1) {
      toreturn += ",";
    }
  }
  return toreturn;
}
console.log(fixA(["string1", [5, [false]], "string2"]));

The issue now is that I have no clue how to convert it back. I've tried a few things but have always gotten stuck on how I convert the arrays back. This is basically what I've tried:

function fixS(string) {
  var toreturn = [];  
  var temp = string.split(",");
  for (var i = 0; i < temp.length; i++) {
    // I could run a check here to see if temp[i] starts with "[", but I'm not sure how to tell where the array ends.
    // If it is an array, then I'd need to pass everything inside of the array back into fixS, making it recursive.
    // The times I tried to do those two things above, I ran into the issue that the commas inside of the sub arrays also split everything, which I don't want (as the recursive function will deal with that).
    toreturn.push(temp[i]);
  }
  return toreturn;
}
console.log(fixS("'string1',[5,[false]],'string2'"));
// This also doesn't return numbers as numbers or booleans as booleans.

Not much there, but it's as far as I've gotten. Any help is appreciated.

Have you considered, or are you aware of, [`JSON.stringify()`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/stringify) or [`JSON.parse()`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/parse)? — David Thomas, Aug 25 '18 at 12:44
No problem at all! (I do applaud you for attempting your own solution though, but until you create your own API for the functionality you're likely to encounter a lot of edge-cases.) — David Thomas, Aug 25 '18 at 12:57

score 3 · Accepted Answer · answered Aug 25 '18 at 12:46

Instead of doing your own bespoke solution, unless you have something that can't be represented in JSON (your example can be), use JSON:

On page load:

var data = JSON.parse(localStorage.getItem("data") || "null");
if (!data) {
    // There wasn't any, initialize
}

or

var data = JSON.parse(localStorage.getItem("data") || "{}");

...if you want a blank object if there is nothing in local storage.

When saving your data:

localStorage.setItem("data", JSON.stringify(data));

score 1 · Answer 2 · answered Aug 25 '18 at 12:49

As David said there's JSON.stringify() & JSON.parse();

you can use those methods :

function save_to_storage(id, anything){
    localStorage.setItem(id, JSON.stringify(anything));
}
function load_from_storage(id){
    return JSON.parse(localStorage.getItem(id));
}

score 0 · Answer 3 · answered Aug 25 '18 at 13:43

0

It can be achieved with help of JSON.stringify and JSON.parse functions. Let me explore with help of code snippet.

var original_arr = ["string1", [5, [false]], "string2"];  // array
// Converting this array into string
var converted_str = JSON.stringify(original_arr); // converted into string
// Converting this string back to array
var new_arr = JSON.parse(converted_str );  // back to array

answered Aug 25 '18 at 13:43

Monil

11
1

I would like to know the reason of downvote. I think I have given right answer with reference to question title of converting the array to string and then string back to the array. I have also tested above code with reference to array to string and then back to array conversation. I would appreciate for valid reason of downvote. Thanks. – Monil Aug 27 '18 at 04:10

score 0 · Answer 4 · answered Aug 25 '18 at 16:34

0

The other answers have already covered it, but note that P5.js also provides functionality for working, saving, and loading JSON directly.

Take a look at the saveJSON() and loadJSON() functions in the reference.

answered Aug 25 '18 at 16:34

Kevin Workman

41,537
9
68
107

How to convert a converted string back into an array?

4 Answers4