Javascript: Retrieve file and line location of function during runtime

问题

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?

回答1:

1. You still cannot access the internal properties through JavaScript.

2. 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.

来源：https://stackoverflow.com/questions/56066523/javascript-retrieve-file-and-line-location-of-function-during-runtime