Read JSON with infinity in R

I'm looking for a way to read a matrix containing an infinite value that is encoded in a JSON file into R. I'm currently getting the furthest using the RJSONIO library for this (rjson and rjsonlite produce an error in my case).

A minimal illustrative example is as follows: (EDIT: this example is not general enough, the method I'm looking for can handle non-finite values that are not generated in R as well)

> library("RJSONIO")

> M <- matrix(c(1:5, Inf), ncol=2, byrow=TRUE); M

     [,1] [,2]
[1,]    1    2
[2,]    3    4
[3,]    5  Inf

> fromJSON(toJSON(M))

[[1]]
[1] 1 2

[[2]]
[1] 3 4

[[3]]
[[3]][[1]]
[1] 5

[[3]][[2]]
NULL

Executing this code will also produce a warning that the non-finite values may not be appropriately represented in JSON.

I'm wondering if there is a work-around to get the infinite values to be correctly represented during the file reading? I'm fine with the file being stored as a list after reading, but not with the last element not being a numeric vector.

Note that I'm not really looking for a post-processing method that converts the non-numeric vectors after having read the entire file: I already have this, but the actual files I'm working with are quite large and nested, so I prefer to not have to rerun through them.