Extension development: support to show functions in console.log

[Jakobud]

• VSCode Version: 1.7.2
• OS Version: Win7 x64

I have the following basic object:

// test.js
module.exports = {
  hello: 'world',
  callback: () => {
    console.log('test!');
  }
}

Using Node.js normally I can easily require this object and utilize it:

const test = require('./test');
console.log(test);

As expected, yields:

{ hello: 'world', callback: [Function: callback] }

However, when I am developing a VSCode extension, if I require this same exact file:

const vscode = require('vscode');
const test = require('./test');

let activate = (context) => {
  let disposable = vscode.commands.registerCommand('myExtension.myCommand', () => {
    console.log(test);
  });
  context.subscriptions.push(disposable);
}
exports.activate = activate;
let deactivate = () => { }
exports.deactivate = deactivate;

I get this:

{ hello: "world" }

The function that I specified in the exported object is completely ignored when it's required into the extension. I've never come across this with normal Node.js development. Can anyone shed some light on this? Is there something obvious I'm doing wrong that I'm just missing?

[Jakobud]

As I'm looking deeper into this, I'm finding 2 things:

1. This doesn't apply only to requiring external objects, but if I define the object itself in extension.js, I get the same result.

2. The functions are still there and are accessible in your code. They just don't show up when using console.log for some reason.

[Jakobud]

More details, looks like console.log(Object.keys(test)); does return an array with the appropriate keys in it.

[bpasero]

This is a result of us using JSON serialisation to convert objects being outputted to output in the debug console. One workaround would be to just do Function.toString() and show the value as string, but people might confuse that with an actual string because we cannot know when deserialising that the thing was a function after all.

I think the way forward here is to get rid of JSON at all and support real objects from extension debug to the repl.

@weinand @isidorn do we already have an item for this to support it for extension development? Similar to #15796

[isidorn]

@bpasero we do not have an item for this already, but @weinand would know better

[jrieken]

This needs a replacer-function when calling JSON.stringify

[Jakobud]

Thank you for the clarification guys. Not really a huge deal breaking priority bug (I don't think?) but I just wanted to make sure I got it submitted.

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