Run a json string function_问答_开发者_运维开发者技术经验分享

开发者 https://www.devze.com 2023-01-21 01:27 出处：网络

I have a json string like this: json = \"{\'run\': \'function() { co开发者_JAVA百科nsole.log(\'running...\'); }\'}\"

I have a json string like this:

json = "{'run': 'function() { co开发者_JAVA百科nsole.log('running...'); }'}"

How do I run that function inside of the json string?

You're going to have to use the eval() (doc) function. A lot of people have a lot of feelings about this function. JSON is best for transporting data, not functions (see JSON). The functions ought to lay in the script on the page. Also there's a syntax error in your posted code (function is wrapped in single quotes ('), and so is console.log's first parameter). But...

json = "{\"run\":\"function() { console.log('running...'); }\"}"; //Fixed, thanks
obj = JSON.parse(json);
eval(obj.run); //Logs "running..."

Update:

Oh, and I was mistaken. Eval doesn't seem to like anonymous functions. With the revised code, it will parse json into an object with a run property that is a String, with value "function() { console.log('running...'); }". But when you eval(obj.run);, you will get a SyntaxError declaring an unexpected (. Presumably, this is the ( in function ().

So, I can think of two ways of dealing with this:

Remove the anonymous function in your actual JSON string (so, make your PHP forget about function () {), and eval it. This means it will be called as soon as you eval it.
What I think you want, is to be able to evaluate it to an anonymous function, that will be called when you want. So, you could write a wrapper function (you would need to follow option 1 for this as well):
```
function returnEval(str) {
    return function () { eval(str); }
}
```
This would allow you to call it. So:
```
obj = JSON.parse(json);
obj.run = returnEval(obj.run);
obj.run(); //Logs "running..."
```

Hope this helps!

JSON is not really intended for that, but here seems to be a good example.

This works for me in Firefox:

var json = "{'run': 'function() { console.log(\\'running...\\'); }'}";
eval('var j = ' + json);
eval('var r = ' + j.run);
r();

Try this, it works:

var JS = { "function" : "alert( new Date().getTime() );" };

new Function ( "", JS["function"] )();

for nested functions you also can use something like this:

jQuery.each( JS, function( method, value ) {
        new Function ( "a, b", "if ( a == 'function' ) { new Function ( '', b )(); }" )( method, value );
} );

I know that thread is old but i want to share with you guys. You can make string a json and parse it easily with these functions.

function makeString(val){
    return JSON.stringify(val, function (key, value) {if (typeof value == 'function') {return value.toString();}return value;});
}

function parseIt(val){
    return JSON.parse(string, function (key, value) {if (value.toString().search("function")>-1) {eval("var func = " + value);return func;}return value;});
}

Without using eval('function()') you could to create a new function using new Function(strName). The below code was tested using FF, Chrome, IE.

<html>
<body>
<button onclick="test()">Try it</button>
</body>
</html>
<script type="text/javascript">
  function test() {

    try {    

        var myJSONObject = {"success" : true, "jsFunc" : "myFunction()"};
        var fnName = myJSONObject.jsFunc;
        var fn = new Function(fnName);
        fn();

      } catch (err) {
        console.log("error:"+err.message);
      }

  }

  function myFunction() {
    console.log('Executing myFunction()');
  }
</script>