JSON.parse具有内部函数

Question

I have a string that if I turn it into OBJ it works correctly.

var obj = JSON.parse('{ "placeholder": "Hello...."} ');

then I put it in the tagEditor plugin in this way $('textarea').tagEditor(obj);

But I also need to evaluate within if there is a function and that it works, in this way.

var obj = JSON.parse('{ "placeholder": "Hello....", "onChange":"function(a,b,c)}{ }"} ');

and I put it....... $('textarea').tagEditor(obj);

but when I do that I get error Uncaught SyntaxError: Unexpected string in JSON at position 38

Actually I want to evaluate the function that is by string, As you can see when I put the event "onchange" and the function within the object this has to evaluate it for the plugin to work Does anyone know how to solve that problem?

Answer 1

You should first declare the function, then call toString on the function (which will automatically escape the ' s, which is the problem in your current syntax):

 function x(a, b, c){ return ''; } const stringified = JSON.stringify({ placeholder: "Hello....", onChange: x.toString() }); 

Specifically, because the string delimiters for the function property value use ' , you need to escape the ' s used inside. (turn

"onChange":"function(a,b,c)}{ return ''; }"

into

"onChange":"function(a,b,c)}{ return \'\'; }"

)

But I wouldn't recommend doing that manually, it'll be pretty tedious and somewhat error-prone - the toString() method is probably a better option.

Answer 2

The syntax is invalid:

var obj = JSON.parse('{ "placeholder": "Hello....", "onChange":"function(a,b,c)}{ return ''; }"} ');

You JSON is quoted properly, but you preempted the single quotes inside the function declaration. So change it to escaped quotes:

EDIT: to then evaluate the function you must use eval() like this. I have no idea what your intent is for the onChange handler so I modified it so it would actually work:

 var obj = JSON.parse('{ "placeholder": "Hello....", "onChange":"function handler(e){ console.log(e.target.value); }"} '); console.log(obj); eval(obj.onChange); document.querySelector('input').onchange = handler; 

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