Unclear documentation for calling functions with fractions

[wouterbeek]

The documentation on https://mathjs.org/docs/datatypes/fractions.html states that "[m]ost functions will determine the type of output from the type of input: [...], a Fraction as input returns a Fraction as output".

I specifically cannot get this to work for fractions. For me, every function that takes only Fraction parameters returns an object of type MathType. This object cannot be stored in a Fraction object without an explicit cast (one per function call) and it cannot be returned by a function that has return type Fraction.

Could the documentation be wrong here? It is required to do an explicit cast after every function call involving fractions?

Here is my example code:

import { all, ConfigOptions, create, Fraction } from 'mathjs'
const config: ConfigOptions = {
  number: 'Fraction',
}
const math = create(all, config)

async function run() {
  const a: Fraction = math.fraction(1)
  const b: Fraction = math.fraction(60)
  const c: Fraction = math.divide(a, b) // <--- wrong type, returns 'MathType'
}

[josdejong]

I think you're hitting the issue that the TypeScript definitions are not up to date for Fraction for many functions, see #2582 (comment)

[wouterbeek]

Ah, that's too bad. I'm closing this issue since it is a duplicate.

[josdejong]

👍