How could a Commando like me check if inputed code is a valid JavaScript source using some JavaScript built-in methods (if any!) or in any other possible way!? (Something like a preparser found in various IDE's like NetBeans, Eclipse, etc)?
I have to check if code is OKAY and then window.eval()-it to the current document instance.
Assuming that your need is to check whether the code will not throw any syntax errors, following is my solution:
var code = "asdfsd = 1";
try {
(function(){
new Function(code);
})()
}
catch(e) {
alert('error');
}
Working Example: http://jsfiddle.net/5NpGa/
new Function(string) is eval in disguise.
new Function(str) doesnt affect the variables in the scope. stackoverflow.com/questions/4599857/…
catch in the proposed solution is going to be triggered only in the case of runtime errors (e.g. variable asdfsd is not defined). But that code is still syntactically valid. asdfsd = 1 1 (note the space between the 1s) is not going to be catched.You could use a lint library like:
http://www.javascriptlint.com/download.htm
EDIT:
Sorry, that's a compiled linter and you're wanting something for on-the-fly. Try jslint: http://jslint.com
You're looking for Crockford's jslint.js. It's the same code that powers http://jslint.com/.
