Undefined control sequence even after defining it about mathjax-node

[dpvc]

You are providing a v3 configuration, but mathjax-node uses MathJax v2, so you would need to use

const converted = await mathjaxNode.typeset({
  math: "\lambda \in \R",
  format: 'TeX',
  mml: true,
  MathJax: {
    TeX: {
      Macros: {
        R: 'Reals',
      }
    }
  }
});

but I'm wondering if you have the correct definition for \R, as this will produce "λ ∈ Reals". You might want to use

        R: '\\mathbf{R}',

or

        R: '\\mathbb{R}',

instead.

Note that MathJax v3 can be used in node directly, so you might also consider switching from mathjax-node to MathJax v3. See the MathJax node demos repository for examples. There are several different ways you can call MathJax v3 from node applications, and there are examples for each; seethe various subdirectories in that repository.

[brunobmello25]

Oh so that's what was happening! Thanks a lot! That solved the problem

I'll close this issue for now, and I'll also consider switching from mathjax-node to mathjax v3. Thanks again for the help!