CODEWITHSUNDEEP
javascriptwebcookies
xai2
xai2

Reputation: 45

Converting a string to array in javascript without eval()

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?

Upvotes: 3

Views: 1094

Answers (3)

colxi
colxi

Reputation: 8730

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 );

Upvotes: 1

CertainPerformance
CertainPerformance

Reputation: 371118

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]);

Upvotes: 5

Matt Way
Matt Way

Reputation: 33189

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)

Upvotes: 1

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