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When using jQuery Ajax, in the Browser console I can see the xhr object has two props / fields in some weird notation [double square brackets, don't think it means array in this case];

First, what exactly are they, and second, can I access these values from my JavaScript code?

[[FunctionLocation]]: jquery-3.3.1.min.js:2
[[Scopes]]: Scopes[4]
0: Closure (w.Callbacks) {e: {…}, t: undefined, n: "", r: undefined, i: Array(0), …}
1: Closure {e: Window, r: document, i: ƒ, o: ƒ, a: ƒ, …}
2: Script {loc: Location, baseRestURL: "http://localhost:60123/MyVirtualDir"}
3: Global {parent: Window, opener: null, top: Window, length: 0, frames: Window, …}

enter image description here

joedotnot
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1 Answers1

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No, You can't access them in your code.

The [[FunctionLocation]] property you see in Inspector is added in V8Debugger::internalProperties() in the debugger's C++ code, which uses another C++ function V8Debugger::functionLocation() to gather information about the function. functionLocation() then uses a number of V8-specific C++ APIs such as v8::Function::GetScriptLineNumber() and GetScriptColumnNumber() to find out the exact information. All APIs described above are exclusively available to C++ code, not JavaScript code. If you are trying to accomplish this task in a platform like Node.js, then you should be able to write a native module. If not, then you are out of luck.

There is another similar question answered here

[[Scopes]] is a private property that Chrome developer tools add and use internally, in C++, here in the source. It displays the variables that are in the scope of a function, i.e. which variables can be accessed from that function.

Riddhijain
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