What is the recommended way to globally define macros? (also, that take arguments)

[hrbigelow]

Before requesting a feature, please search for existing issues.

I was reading through #2070 and have successfully used the technique mentioned there to define global macros that take arguments:

    let macros = {
      '\\B': '\\boldsymbol{#1}',
      '\\proj': '#1_{\\small \\parallel #2}'
    };
    document.addEventListener("DOMContentLoaded", function() {
        renderMathInElement(document.body, {
          macros: macros,
          
          // customised options
          // • auto-render specific keys, e.g.:
...

Since the post is a few years old, I wonderedi f there some HOWTO or update that I should also read.

Thanks very much!

[edemaine]

Thanks for checking in. That is still the recommended method. In the future, you might use the Discussions tab.

[hrbigelow]

Great, thanks. Actually, would it also be possible to achieve this at the content level, where Katex first parses (but doesn't render anything for) \\newcommand statements like:

    katex.renderToString(
        String.raw`\newcommand\proj[2]{#1_{\small \parallel #2}}`
    )

so that the global options.macros object gets updated? I saw this other post: #3112 but it looks still open so not sure what the status is.

Thanks again

[edemaine]

You can use

const macros = {};
katex.renderToString(
        String.raw`\newcommand\proj[2]{#1_{\small \parallel #2}}`,
        {macros, globalGroup: true});
// render other things with macros

Note that you need to pass in the same macros object to all KaTeX calls in order to share macros.

[hrbigelow]

Hi, this technique worked (Thank you!). But I was wondering if there is any way to tell Katex not to render anything when it processes macro definitions. At the moment, I see:

const macros = {};
katex.renderToString(
        String.raw`\newcommand\B[1]{\boldsymbol{#1}}`,
        { macros, globalGroup: true });
// '<span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow></mrow><annotation encoding="application/x-tex">\\newcommand\\B[1]{\\boldsymbol{#1}}</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"></span></span>' 

[edemaine]

katex.renderToString is just returning a string; it doesn't output anything. Because you're running it in console, you're seeing the return value in console, but if you run this in a script or otherwise, there won't be any output.

[hrbigelow]

Oh, sorry, I shouldn't have used the word "output". What I was really asking is, is there a way to tell katex.renderToString to return the empty string if it processes a macro definition, rather than returning the string as I've shown above?