Node v10 uses V8 6.8 (two years old), and the latest version of V8 is 8.4.
On Thursday, July 9, 2020 at 1:42:07 PM UTC-7, Nupoor Kotasthane wrote:
>
> 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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