I am able to reproduce the same behavior with Node.js v10.21.0.
On Tuesday, June 30, 2020 at 5:46:07 PM UTC-7, Nupoor Kotasthane wrote:
>
> The observation here was that we are able to inspect, only the objects
> that are imported/exported, using Debugger.evaluateOnCallFrame. For all the
> other objects, when evaluated, we just get reference errors.
> Any insight on why this may be happening will be great!
>
> Thanks,
> Nupoor
>
>
>
> On Friday, June 26, 2020 at 9:07:45 AM UTC-7, Nupoor Kotasthane wrote:
>>
>> Hi Ben,
>>
>> Here's the example I have been using:
>> I have two mjs files:
>> sample.mjs:
>> import {a} from '/testmod.mjs';
>> let p = 9;
>> var t1 = 1;
>> var t2 = 2;
>> var t3 = 3;
>> var t4 = 4;
>> var temp = 1;
>> temp = 2* temp;
>> temp = 3* temp;
>> temp
>>
>> testmod.mjs:
>> export var a = 10;
>> export var b = 20;
>> export var c = 30;
>>
>> Once I start debugging sample.mjs, I step over a little and reach line 5
>> and I get the following notification from inspector:
>> {
>> "method": "Debugger.paused",
>> "params": {
>> "callFrames": [
>> {
>> "callFrameId": "{\"ordinal\":0,\"injectedScriptId\":1}",
>> "functionName": "",
>> "functionLocation": {
>> "scriptId": "11",
>> "lineNumber": 0,
>> "columnNumber": 0
>> },
>> "location": {
>> "scriptId": "11",
>> "lineNumber": 5,
>> "columnNumber": 9
>> },
>> "url": "/sample.mjs",
>> "scopeChain": [
>> {
>> "type": "module",
>> "object": {
>> "type": "object",
>> "className": "Object",
>> "description": "Object",
>> "objectId": "{\"injectedScriptId\":1,\"id\":19}"
>> },
>> "startLocation": {
>> "scriptId": "11",
>> "lineNumber": 0,
>> "columnNumber": 0
>> },
>> "endLocation": {
>> "scriptId": "11",
>> "lineNumber": 10,
>> "columnNumber": 0
>> }
>> },
>> {
>> "type": "global",
>> "object": {
>> "type": "object",
>> "className": "global",
>> "description": "global",
>> "objectId": "{\"injectedScriptId\":1,\"id\":20}"
>> }
>> }
>> ],
>> "this": {
>> "type": "undefined"
>> }
>> }
>> ],
>> "reason": "other",
>> "hitBreakpoints": []
>> }
>> }
>>
>>
>> At this point I want to inspect variable "p". A
>> Debugger.evaluateOnCallFrame request to inspector with the parameter "p"
>> returns:
>> {
>> "id": 12,
>> "result":
>> {
>> "result":
>> {
>> "type": "object",
>> "subtype": "error",
>> "className": "ReferenceError",
>> "description": "ReferenceError: p is not defined\n at eval (eval at
>> <anonymous> (/sample.mjs:6:10), <anonymous>:1:1)\n at /sample.mjs:6:10",
>> "objectId": "{\"injectedScriptId\":1,\"id\":21}"
>> }
>> ,
>> "exceptionDetails":
>> {
>> "exceptionId": 1,
>> "text": "Uncaught",
>> "lineNumber": 0,
>> "columnNumber": 0,
>> "scriptId": "14",
>> "stackTrace":
>> {
>> "callFrames":
>> [
>> {
>> "functionName": "",
>> "scriptId": "14",
>> "url": "",
>> "lineNumber": 0,
>> "columnNumber": 0
>> }
>> ,
>> {
>> "functionName": "",
>> "scriptId": "11",
>> "url": "/sample.mjs",
>> "lineNumber": 5,
>> "columnNumber": 9
>> }
>> ]
>> }
>> ,
>> "exception":
>> {
>> "type": "object",
>> "subtype": "error",
>> "className": "ReferenceError",
>> "description": "ReferenceError: p is not defined\n at eval (eval at
>> <anonymous> (/sample.mjs:6:10), <anonymous>:1:1)\n at /sample.mjs:6:10",
>> "objectId": "{\"injectedScriptId\":1,\"id\":22}"
>> }
>> }
>> }
>> }
>>
>> The expected outcome here would have been to see the actual value of
>> variable "p". I am seeing similar response for all variables declared in
>> sample.mjs and that is unexpected. However, the imported object "a" can
>> does not yield the same response. Inspector returns the right value for
>> "a".
>>
>> At the same point if I send Runtime.getProperties request to V8 with the
>> current module scope's object id: '{\"injectedScriptId\":1,\"id\":19}' as
>> parameter, I only see the following:
>> {
>> "id": 15,
>> "result":
>> {
>> "result":
>> [
>> {
>> "name": "a",
>> "value":
>> {
>> "type": "number",
>> "value": 10,
>> "description": "10"
>> }
>> ,
>> "writable": true,
>> "configurable": true,
>> "enumerable": true,
>> "isOwn": true
>> }
>> ]
>> }
>> }
>>
>> I do not see the other variables in sample.mjs in the above response.
>>
>> Do you still think this is expected behavior or do you suspect there is
>> another issue here?
>>
>> Please let me know. Any help will be great!
>>
>> Thanks,
>> Nupoor
>>
>>
>>
>>
>>
>>
>> On Friday, June 26, 2020 at 4:11:04 AM UTC-7, Ben Noordhuis wrote:
>>>
>>> On Thu, Jun 25, 2020 at 2:35 AM Nupoor Kotasthane <nupoo...@gmail.com>
>>> wrote:
>>> >
>>> > I also notice that the 'this' object in the Debugger.CallFrame objects
>>> have their 'type' set to 'undefined' when debugging ES6 modules. I also
>>> notice that the variables declared in the starting module are missing from
>>> the scope when I try to inspect the scope object with
>>> Runtime.getProperties. Is this expected behavior?
>>> >
>>> >
>>> >
>>> > On Tuesday, June 23, 2020 at 2:56:57 PM UTC-7, Nupoor Kotasthane
>>> wrote:
>>> >>
>>> >> Hi Ben,
>>> >>
>>> >> We have embedded V8 version 6.7 in our product. We use it to run and
>>> debug JavaScript. While debugging scripts is working okay, debugging ES6
>>> modules using the inspector has this one problem. When using
>>> Debugger.evaluateOnCallFrame to inspect variables we keep getting an
>>> inspector response with reference errors saying the variables are not
>>> defined. This is true for all locally declared variables within the current
>>> scope in the "mjs" module (I do not see this problem with the imported
>>> module, only the importing module).
>>> >>
>>> >> It seems like symbols are not generated for the importing 'mjs'
>>> module. So do we have to do anything special for modules for this to work?
>>> I can share my example if and inspector responses if that will help.
>>> >>
>>> >> Thanks,
>>> >> Nupoor
>>>
>>> It's possible I'm misunderstanding you but it sounds like it's working
>>> as expected.
>>>
>>> ES modules run in strict mode. Function calls (not method calls) have
>>> `this` set to `undefined`, and top-level variables are local to the
>>> module, not global.
>>>
>>> If that's not what you mean, can you share some example code and
>>> expected vs. actual output?
>>>
>>
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