Eval() = Unexpected token : error

Question

I tried this simple JavaScript code:

eval('{"Topics":["toto","tata","titi"]}')

In the Chrome console, for example, this returns

SyntaxError: Unexpected token :

I tried the JSON on JSONLint and it's valid.

Do you see the bug?

Answer 1

FWIW, use JSON.parse instead. Safer than eval.

Answer 2

You have to write like this

eval('('+stringJson+')' );

to convert an string to Object

Hope I help!

Answer 3

Because eval does not force an expression context and the string provided is an invalid JavaScript program, thus the first three tokens (and how they are looked at) are:

{            // <-- beginning of a block, and NOT an Object literal
"Topics"     // <-- string value, okay (note this is NOT a label)
:            // <-- huh? expecting ";" or "}" or an operator, etc.

Happy coding.

Answer 4

Number one: Do not use eval.

Number two. Only use eval to make something, well be evaluated. Like for example:

eval('var topics = {"Topics":["toto","tata","titi"]}');

Answer 5

Because that's evaluating an object. eval() requires you to pass in syntactically valid javascript, and all you're doing is passing in a bare object. The call should be more like:

eval('var x = {"Topics":etc...}');

Answer 6

USE:

function evalJson(jsArray){ eval("function x(){ return "+ jsArray +"; }"); return x(); }

var yourJson =evalJson('{"Topics":["toto","tata","titi"]}');

console.log(yourJson.Topics[1]); // print 'tata''

Answer 7

if you are using JQuery use the function $.parseJSON(), worked for me, had the same problem

Answer 8

if you want to make an array use the below code

var jsonObject = eval('(' +"["+ response + "]"+')');