Setting value to undefined removes property

[danrot]

I am setting a value of undefined on an object using your library, and this removes the property completely. I would like to keep the property and really set its property to undefined.

I also put an example here:

const a = {value: 5};
jsonpointer.set(a, 'value', undefined);
console.log(a); // outputs something like {}, but I would like to have {value: undefined}

[jperasmus]

Looks like it is intentional:

node-jsonpointer/jsonpointer.js

Line 42 in 2a9875e

if (value === undefined) delete obj[part]

[janl]

yeah, this is by design #27

I’d accept a PR that implements set(obj, pointer, value, {allowUndefinedValue: true}). Bonus points for a way to instantiate a set fun that has that option bound to it for each invocation.

Please file a PR directly.

[jperasmus]

What about exposing a new setup or settings function that can be called to globally apply this and possible future config options?

jsonpointer.settings({ allowUndefinedValue: true })

Is this something you would be interested in?

[janl]

sure, all of this sounds good

[johnmiroki]

One thing to note is there is NOT undefined in JSON, while undefined is a valid value in JavaScript object. So for [1, undefined, 2] in JavaScript, when it's converted to JSON, it becomes [1, null, 2], which may have undesired effect.