Javascript parse string as es6 function

Question

I'm getting string representation for es6 function like this

"return (...args) => {↵    console.log('HIGHLIGHTLOADER', args);↵  };"

from this string, I need to create a function

const func = (...args) => {
  console.log('HIGHLIGHTLOADER', args);
}

Without using eval How can i parse this string?.

By "parse" - do you mean you want to create an executable function you can directly call? Or by "parse" do you mean you want the AST of the function? If it's the former then no, you cannot. That's exactly what eval is for. And what you're asking is horribly unsafe. — Dai
– Dai, Commented Nov 3, 2020 at 9:44
@WimalWeerawansa What is the nature of this application? How does it run (in the browser? server-side NodeJS? something else?). Does your application design actually call for the execution of untrusted, unverified user-supplied scripts? How does your program handle someone providing a script that steals cookies and sends them to a criminal botnet or does JavaScript cryptocurrency mining? — Dai
– Dai, Commented Nov 3, 2020 at 9:49

Andreas · Accepted Answer · 2020-11-03 10:02:18Z

5

Use the Function constructor (after removing invalid characters like ↵)

const input = "return (...args) => { console.log('HIGHLIGHTLOADER', args); };"
const func = (new Function(input)());

func(1, 2, 3);

answered Nov 3, 2020 at 10:02

Andreas

21.9k7 gold badges52 silver badges58 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Dai Over a year ago

I note that this approach has the same security issues as eval - so any company policy that forbids eval must also forbid use of the Function(string) constructor.

Andreas Over a year ago

🠕 This. If you really want to stick with this approach, then only ever use this if you're 100% sure that the content of input will be safe and not controlled by anyone else but you.

Collectives™ on Stack Overflow

Javascript parse string as es6 function

1 Answer 1

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related