Javascript: Retrieve file and line location of function during runtime

Question

I am trying to get the file and line location of a function I saved in an object. If I am logging the object to the Chrome Dev Tools I see this:

Can I somehow from inside the code access [[FunctionLocation]]? Or is this something the Chrome Dev Tools add to the object? If so, is it possible to retrieve the function location when I am developing a Chrome Dev Tools extension or a Chrome extension?

[This should better be able to help answer your question](https://stackoverflow.com/questions/41146373/access-function-location-programmatically), but it appears to be no. — Brett Fuller, May 09 '19 at 21:17
Looks like you asked a two part question and rather than start another thread the second part of your questions was not answered by the above link and is what I am curious about as well. 1. Can you access it in dev tools from the console? The link says no, mind you that was a couple years ago. 2. Are we able to access that from within an extension script? I have searched the APIs but cannot find it referenced and am developing an extension and I would like to find functions locations as part of the data points I am exposing. — mike-pz, Aug 07 '19 at 13:11

score 2 · Accepted Answer · answered Aug 30 '19 at 05:02

You still cannot access the internal properties through JavaScript.

The information is exposed through the Chrome DevTools Protocol, as an InternalPropertyDescriptor. This is observable through for example Node.js:

global.a = () => { /* test function */ };

const s = new (require('inspector').Session)();
s.connect();

let objectId;
s.post('Runtime.evaluate', { expression: 'a' }, (err, { result }) => {
  objectId = result.objectId;
});
s.post('Runtime.getProperties', { objectId }, (err, { internalProperties }) => {
  console.log(internalProperties);
});

yields

[
  {
    name: '[[FunctionLocation]]',
    value: {
      type: 'object',
      subtype: 'internal#location',
      value: [Object],
      description: 'Object'
    }
  },
  {
    name: '[[Scopes]]',
    value: {
      type: 'object',
      subtype: 'internal#scopeList',
      className: 'Array',
      description: 'Scopes[2]',
      objectId: '{"injectedScriptId":1,"id":24}'
    }
  }
]

with Node.js v12.3.1.

Chrome extensions may interact with the Chrome DevTools protocol through chrome.debugger. I am not familiar with how DevTools extensions work, but you may find the Integrating with DevTools page to be insightful.

Javascript: Retrieve file and line location of function during runtime

1 Answers1

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