Validates mathjax using katex

validate.R

ctx <- V8::v8()
ctx$source('https://cdn.jsdelivr.net/npm/[email protected]/dist/katex.min.js')
ctx$eval('function validate(s){var out = {result: "ok", warnings:[]}; try{console.warn=function(w){out.warnings.push(w);};katex.renderToString(s)} catch (e) {out.result = e.name; out.position = e.position; out.message = e.message}; return out;}')

# Parsing error
ctx$call('validate', "E(y) = \\boldmath{\\mu}")

# OK but with warnings:
ctx$call('validate', "s*ₓᵢ = sₓᵢ √(VIFₓᵢ⁻¹) √((n-1)/(n-p))")