Is there a way to capture a variable access?

Asked Mar 24 '20 at 14:14

Active Mar 24 '20 at 14:20

Viewed 34 times

I am currently having a problem to which a potential solution is always returning something when trying to access an undefined property.

As an example consider this:

const obj = {}
obj.myMethod() // will throw an error as obj.myMethod is undefined
populateObj(obj)
obj.myMethod() // will work now that myMethod is defined

It is not possible to set obj.myMethod to some default value beforehand as the names of the properties of obj are unknown (their names are determined by an external server). So I was thinking of having obj return some default method whenever accessing an undefined property. I am guessing that there is no way of doing this in javascript but thought I'd ask just in case.

Thanks in advance!

Note: I know I could introduce a obj.get method to return either a default value or the one set in obj, however I am trying to make this work with object destructuring.

asked Mar 24 '20 at 14:14

timgfx

try assigning with an empty function – User863 Mar 24 '20 at 14:16
It seems like the solution to this thread will work: https://stackoverflow.com/questions/6600868/set-default-value-of-javascript-object-attributes – timgfx Mar 24 '20 at 14:17
@User863 that won't work as the names of the properties of obj are unknown beforehand. I might have found a way to do this with proxies though, I have posted a link above^ – timgfx Mar 24 '20 at 14:18
"return some default method " -default method - how it should be ? Example pls – M A Salman Mar 24 '20 at 14:19
`obj = new Proxy({}, { get: () => () => {} });` – ASDFGerte Mar 24 '20 at 14:21
@ASDFGerte thanks, I will try using Proxies :) – timgfx Mar 24 '20 at 14:22
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Optional_chaining – Teemu Mar 24 '20 at 14:23
Does this answer your question? [Set default value of javascript object attributes](https://stackoverflow.com/questions/6600868/set-default-value-of-javascript-object-attributes) – ASDFGerte Mar 24 '20 at 14:24
@ASDFGerte Yes it does, thanks & have a great day – timgfx Mar 24 '20 at 14:25

Is there a way to capture a variable access?

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