Macros

MathLive has over 800 LaTeX commands predefined. Some are primitives but others are macros, that is commands defined with a LaTeX expression. You can extend MathLive with your own macros.

Adding/Removing Macros

To add a macro use mf.macros = {...mf.macros, ...}.

If you do not include the ...mf.macros call, all the standard macros will be turned off.

The example below will define a new command, \average, which will be replaced by \operatorname{average}, that is displayed as a single unit using an upright font.

Try changing \operatorname to \mathbf to see the difference.

const mf = document.getElementById('mf');
mf.macros = { ...mf.macros,
  average: '\\operatorname{average}',
};

<math-field id="mf">\average([2, 4, 8])}</math-field>

You can use standard LaTeX commands in the definition of a macro. For example, the following macro definition uses the \, and \; commands to insert horizontal spacing and {}^ to place the \prime command on the subscript line.

mf.macros = { ...mf.macros,
  minutes: "\\,{}^\\prime\\;",
  seconds: "\\,\\doubleprime\\;",
};

The macro definition can contain up to eight arguments, represented by #1 to #9.

const mf = document.getElementById('mf');
mf.macros = {...mf.macros, 
  smallfrac: '{}^{#1}\\!\\!/\\!{}_{#2}',
};

<math-field id="mf">\smallfrac{5}{7}+\frac{5}{7}</math-field>

By default, a macro command behaves as a group whose subcomponents cannot be modified. This behavior can be controlled using the captureSelection flag in the expanded definition of a macro.

To define a macro whose content is selectable and editable set captureSelection to false.

const mf = document.getElementById('mf');
mf.macros = {...mf.macros,
  smallfrac: {
    args: 2,
    def: '{}^{#1}\\!\\!/\\!{}_{#2}',
    captureSelection: false,
  },
};

<math-field id="mf">\scriptCapitalE=\smallfrac{5}{7}+\frac{5}{7}</math-field>

To remove a macro set its definition to undefined:

const mf = document.getElementById('mf');
mf.macros = {...mf.macros, diamonds: undefined };

<math-field id="mf">\diamonds</math-field>

Adding a Matching Shortcut

By defining a new macro, a new LaTeX command is added to the dictionary of commands that can be used in a LaTeX expression.

To input a macro, type \ followed by the macro name, then RETURN

Custom macros are also included in the value of the mathfield expressed as a LaTeX string (mf.value).

It may also be convenient to associate the macro with an inline shortcut. Inline shortcuts can be typed without having to enter the LaTeX editing mode (without having to type the \ key).

To define an associated inline shortcut, use the inlineShortcuts option.

const mf = document.getElementById('mf');
//
mf.macros = {...mf.macros,
  // This means that the command macro `\minutes`
  // will be replaced with `\,{}^\\prime\\;`
  minutes: '\\,{}^\\prime\\;',
  seconds: '\\,\\doubleprime\\;',
};
//
mf.inlineShortcuts = {...mf.inlineShortcuts,
  // This means that typing the inline shortcut 
  // "minutes" will insert the command "\minutes"
  minutes: '\\minutes', 
  seconds: '\\seconds',
};

<math-field id="mf">
  3\minutes 15\seconds
</math-field>

Inspecting Available Macros

To view the available macros, inspect the macros property:

const mf = document.getElementById('mf');
console.log(mf.macros);

<math-field id='mf'>x=\frac{-b\pm \sqrt{b^2-4ac}}{2a}</math-field>

Disabling Macros

To turn off all macros, use mf.macros = {}.