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transform.ToMath

This feature was introduced in Hugo 0.132.0 and is marked as experimental.

This does not mean that it's going to be removed, but this is our first use of WASI/Wasm in Hugo, and we need to see how it works in the wild before we can set it in stone.

Arguments​

EXPRESSION : The math expression to render using KaTeX.

OPTIONS : A map of zero or more options.

Options​

These are a subset of the KaTeX options.

output : (string). Determines the markup language of the output. One of html, mathml, or htmlAndMathml. Default is mathml.

With html and htmlAndMathml you must include KaTeX CSS within the head element of your base template. For example:

<head>
  ...
  <link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/katex@0.16.11/dist/katex.min.css" integrity="sha384-nB0miv6/jRmo5UMMR1wu3Gz6NLsoTkbqJghGIsx//Rlm+ZU03BU6SQNC66uf4l5+" crossorigin="anonymous">
  ...
</head>

displayMode : (bool) If true render in display mode, else render in inline mode. Default is false.

leqno : (bool) If true render with the equation numbers on the left. Default is false.

fleqn : (bool) If true render flush left with a 2em left margin. Default is false.

minRuleThickness : (float) The minimum thickness of the fraction lines in em. Default is 0.04.

macros : (map) A map of macros to be used in the math expression. Default is {}.

throwOnError : (bool) If true throw a ParseError when KaTeX encounters an unsupported command or invalid LaTex. See error handling. Default is true.

errorColor : (string) The color of the error messages expressed as an RGB hexadecimal color. Default is #cc0000.

Examples​

Basic​

{{ transform.ToMath "c = \\pm\\sqrt{a^2 + b^2}" }}

Macros​

{{ $macros := dict 
    "\\addBar" "\\bar{#1}"
    "\\bold" "\\mathbf{#1}"
}}
{{ $opts := dict "macros" $macros }}
{{ transform.ToMath "\\addBar{y} + \\bold{H}" $opts }}

Error handling​

There are 3 ways to handle errors from KaTeX:

  1. Let KaTeX throw an error and make the build fail. This is the default behavior.
  2. Handle the error in your template. See the render hook example below.
  3. Set the throwOnError option to false to make KaTeX render the expression as an error instead of throwing an error. See [options].