Convert string array "[1,2,3]" to array of number in Javascript - Stack Overflow

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I have been searching for a solution but I only found the convertion from ["1","2","3"] to [1,2,3], but my question is how to convert this: "[1,2,3]" to [1,2,3].

It might be clear for many of you but for me not.

I have been searching for a solution but I only found the convertion from ["1","2","3"] to [1,2,3], but my question is how to convert this: "[1,2,3]" to [1,2,3].

It might be clear for many of you but for me not.

• javascript
• arrays

Share Improve this question Follow edited Jun 9, 2015 at 11:42 5511002233 51388 silver badges1919 bronze badges asked Jun 9, 2015 at 10:00 karlihnoskarlihnos 42511 gold badge77 silver badges2424 bronze badges

Add a comment  | 

6 Answers 6

Sorted by: Reset to default 11

There are a few ways:

• Using the already-mentioned: eval("[1,2,3]")
• Using the already-mentioned: JSON.parse("[1,2,3]")
  You can visit https://github.com/koldev/JsonParser and get the oficial implementation for browsers that don't have this method, like IE7.
• Using jQuery's JSON interpreter: $.parseJSON("[1,2,3]")
• Using the function constructor: Function("return [1,2,3];")()
• Using any constructor: []["filter"]["constructor"]("return [1,2,3]")() (Thanks to JSF*ck)

The safest option is to use the JSON package, either from jQuery or your browser's native one.

Remember that eval is evil! It allows to execute arbitrary code.
The same goes for the Function constructors, but with those you can add 'return' to it.
If you do eval("[1,2,3]; evil();"), the evil() function will execute, while Function("return [1,2,3]; evil();") will prevent the execution of evil().
This is not the perfect solution, since one can still do Function("return evil() || [1,2,3];"), and evil() will be executed. But, in this case, [1,2,3] is only returned if evil() returns a falsy value ("", null, 0, false, ...).

Use the JSON.parse("[1,2,3]");

working example http://jsfiddle.net/bcguevd2/

You could also parse it by yourself:

var s = '[1,2,3]';
var a = s.slice(1, -1).split(',').map(Number);
// .slice(1, -1) -> "1,2,3"
// .split(',')   -> ["1", "2", "3"]
// .map(Number)  -> [1, 2, 3]

Variation:

var a = (s.match(/-?\d+/g) || []).map(Number);
// .match(/-?\d+/g)     -> ["1", "2", "3"]

// '[]'.match(/-?\d+/g) -> null
// (null || [])         -> []

One solution is to use JSON.parse()

JSON.parse("[1,2,3]")

Also you can use eval() if the source is a trusted one(Don't use eval needlessly!) like

eval("[1,2,3]")

You can use eval with the following caveat Don't use eval needlessly!

var myArray = eval("[1,2,3]");

    Well, "[1,2,3]" is a String object.
    You need to deserialize it using JSON.parse().

    e.g: 
    var arr = "[1,2,3]"
    JSON.parse(arr)

    output will be >> [1,2,3]

Note: browser console don't detect JSON.parse() or JSON.stringify()
You have to do it in your code editor.

I have been searching for a solution but I only found the convertion from ["1","2","3"] to [1,2,3], but my question is how to convert this: "[1,2,3]" to [1,2,3].

It might be clear for many of you but for me not.

I have been searching for a solution but I only found the convertion from ["1","2","3"] to [1,2,3], but my question is how to convert this: "[1,2,3]" to [1,2,3].

It might be clear for many of you but for me not.

• javascript
• arrays

Share Improve this question Follow edited Jun 9, 2015 at 11:42 5511002233 51388 silver badges1919 bronze badges asked Jun 9, 2015 at 10:00 karlihnoskarlihnos 42511 gold badge77 silver badges2424 bronze badges

Add a comment  | 

6 Answers 6

Sorted by: Reset to default 11

There are a few ways:

• Using the already-mentioned: eval("[1,2,3]")
• Using the already-mentioned: JSON.parse("[1,2,3]")
  You can visit https://github.com/koldev/JsonParser and get the oficial implementation for browsers that don't have this method, like IE7.
• Using jQuery's JSON interpreter: $.parseJSON("[1,2,3]")
• Using the function constructor: Function("return [1,2,3];")()
• Using any constructor: []["filter"]["constructor"]("return [1,2,3]")() (Thanks to JSF*ck)

The safest option is to use the JSON package, either from jQuery or your browser's native one.

Remember that eval is evil! It allows to execute arbitrary code.
The same goes for the Function constructors, but with those you can add 'return' to it.
If you do eval("[1,2,3]; evil();"), the evil() function will execute, while Function("return [1,2,3]; evil();") will prevent the execution of evil().
This is not the perfect solution, since one can still do Function("return evil() || [1,2,3];"), and evil() will be executed. But, in this case, [1,2,3] is only returned if evil() returns a falsy value ("", null, 0, false, ...).

Use the JSON.parse("[1,2,3]");

working example http://jsfiddle.net/bcguevd2/

You could also parse it by yourself:

var s = '[1,2,3]';
var a = s.slice(1, -1).split(',').map(Number);
// .slice(1, -1) -> "1,2,3"
// .split(',')   -> ["1", "2", "3"]
// .map(Number)  -> [1, 2, 3]

Variation:

var a = (s.match(/-?\d+/g) || []).map(Number);
// .match(/-?\d+/g)     -> ["1", "2", "3"]

// '[]'.match(/-?\d+/g) -> null
// (null || [])         -> []

One solution is to use JSON.parse()

JSON.parse("[1,2,3]")

Also you can use eval() if the source is a trusted one(Don't use eval needlessly!) like

eval("[1,2,3]")

You can use eval with the following caveat Don't use eval needlessly!

var myArray = eval("[1,2,3]");

    Well, "[1,2,3]" is a String object.
    You need to deserialize it using JSON.parse().

    e.g: 
    var arr = "[1,2,3]"
    JSON.parse(arr)

    output will be >> [1,2,3]

Note: browser console don't detect JSON.parse() or JSON.stringify()
You have to do it in your code editor.

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