I want to implement a counter for unique articles visited in my website, basically storing the ids of the articles the user has visited in a cookie. My issue is that the recovered value is, of course, a string. How would you convert a string that looks like this "['test','b','c']" to an array? Using eval is not advised, right?
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3 Answers
Use JSON.parse to turn a string into an array:
const string = '["test","b","c"]';
const arr = JSON.parse(string);
console.log(arr[0]);Note that you need to have proper JSON formatting, though - keys and non-numeric values need to have double quotes. Easiest to serialize automatically with JSON.stringify:
const arr = ["test","b","c"];
const str = JSON.stringify(arr);
console.log(str);If you absolutely cannot change the single-quotes in the string you're working with originally, then use replace to turn it into something parseable:
const str = "['test','b','c']";
const jsonFormattedStr = str.replace(/'/g, '"');
const arr = JSON.parse(jsonFormattedStr);
console.log(arr[1]);
answered Apr 11, 2018 at 1:26
CertainPerformance
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5 Comments
ibrahim mahrir
JSON.parse won't work on the string provided by OP, though.
CertainPerformance
Right, which is why he should be using
JSON.stringify to take care of the formatting problems automatically.
Matt Way
Not sure that makes sense. He said he can only get the array as a string initially.
JSON.stringify is used to convert objects to strings, not cleanup formatting problems.
Taki
you could replace the
' with " and then parse it (to work with the OP) JSON.parse(string.replace(new RegExp('\'', 'g'), '"'));
erosman
As I am also searching for a solution, sadly the
replace() fails in ['test "one"','b','c']While using JSON.parse() is the correct way to convert data strings to usable objects, the string in your question is not valid JSON syntax. Namely the single quotes will result in an unexpected token error.
If your only issue is the quotes, then it becomes trivial to prepare your data for parsing:
var str = "['test','b','c']"
// convert to double quotes
str = str.split('\'').join('"')
// now parse
var arr = JSON.parse(str)
console.log(arr)Comments
You need to convert the quotes to double quotes, and then use JSON.parse
let string = "['test','b','c']";
// replace quotes with double quotes
let stringFixed = string.replace(/'/g, '"');
// parse the string
let result = JSON.parse( stringFixed );
