fromJSON - rebuild sparse matrix from results of toJSON

[slutske22]

Perhaps this is just a lack of understanding, but here's what I'm trying to do. I create a matrix in a NodeJS application. After some manipulation, it needs to be sent to the front end, and manipulated further.

To send it, it needs to be serialized, which can be done with the toJSON method. The results of a toJSON method look something like this:

How can I transform this back into a sparse matrix on the front end, with all the utility of the class methods (.set, .get, Symbol[Iterator], etc)? Is there a simple way to do that? Surely I must be missing something. Thank you!

[josdejong]

You can stringify and parse like:

const myMatrix = math.sparse([[1, 2], [3, 4]]) // SparseMatrix
const myStringifiedMatrix = JSON.stringify(myMatrix) // string

// ...do something: persist, or transfer, or something else

const myRevivedMatrix = JSON.parse(myStringifiedMatrix, math.reviver) // SparseMatrix

You'll need a mathjs instance in the frontend too, then you can use JSON.parse(..., math.reviver). If you know you're dealing with a SparseMatrix you could also directly call SparseMatrix.fromJSON(myStringifiedMatrix).

See docs: https://mathjs.org/docs/core/serialization.html

[slutske22]

SparseMatrix.fromJSON(myStringifiedMatrix) is exactly what I was looking for!

I realize it is indeed in the docs, but I think my biggest issue is the way the docs are organized -there's a wealth of information in the reference section, but you sort of have to dig to realize its there. Perhaps a dedicated docs website, with a left-hand nested menu, where its very obvious what classes are available, and all the methods on a class, would be helpful. Anyway, I'm just nitpicking, thank you for your answer and this library!

[josdejong]

👍

I realize it is indeed in the docs, but I think my biggest issue is the way the docs are organized -there's a wealth of information in the reference section, but you sort of have to dig to realize its there. Perhaps a dedicated docs website, with a left-hand nested menu, where its very obvious what classes are available, and all the methods on a class, would be helpful. Anyway, I'm just nitpicking, thank you for your answer and this library!

Yeah, agree, thanks for your suggestions. Related: #1769