How to define custom macros in MathJax

Question

I'm trying to define custom macros used in LaTeX files in MathJax.

Can define simple macros (single parameter) without any issue such as;

\newcommand{\braket}[1]{\langle #1 \rangle}

as

Macros: {
    braket: ['{\\langle #1 \\rangle}', 1]
}

But struggle with complicated ones;

\newcommand{\Abs}[2][]{\left\lvert#2\right\rvert_{\text{#1}}}

trying to define it like;

Macros: {
    Abs: ['{\\left\\lvert#2\\rvert_{\\text{#1}}}', 2]
}

but no luck.

This is how it is used in LaTeX file

\begin{align}\nonumber
    p_e = \Abs{\braket{e|\psi(t)}}^2 = \sin^2\Omega t\, .
\end{align}

Not sure where I did wrong.

I'm not a LaTeX expert, but just a developer trying to display LaTeX files on a web app (for Quantum Physics community), so I would greatly appreciate your help. thanks.

P.S this question was asked and closed on SE they redirected me to SO.

Answer 1

I've updated the codepen from my comment.

Primarliy, you forgot a \\right; I also modified your macro definition so that it has an optional parameter. In other words, something along the lines of:

Macros: {
    braket: ['{\\langle #1 \\rangle}', 1],
   Abs: ['\\left\\lvert #2 \\right\\rvert_{\\text{#1}}', 2, ""]
}},