To uniquely style the initial Group Header, you can implement some strategies outlined in the MUI documentation.
Enabling the Autocomplete Group By feature showcased in the example titled With categories, a live demo and source code are provided for reference.
The MUI illustration involves:
1. options
An array of options where each option object includes a firstLetter property:
const options = top100Films.map((option) => {
const firstLetter = option.title[0].toUpperCase();
return {
firstLetter: /[0-9]/.test(firstLetter) ? '0-9' : firstLetter,
...option,
};
});
2. Autocomplete options property
The Autocomplete options should be set to an array of options arranged by the firstLetter.
...
<Autocomplete
id="grouped-demo"
options={options.sort((a, b) => -b.firstLetter.localeCompare(a.firstLetter))}
groupBy={(option) => option.firstLetter}
...
To execute correct sorting (
options.sort((a, b) => -b.firstLetter.localeCompare(a.firstLetter))
), it should happen before the component's
return statement. The sorted result should be stored in a variable (e.g.
sortedOptions) with component-level scope. This ensures that
sortedOptions is accessible to any function within the component using Autocomplete. With this update in place, the code would appear as follows:
...
<Autocomplete
id="grouped-demo"
options={ sortedOptions }
groupBy={(option) => option.firstLetter}
...
3. Autocomplete renderGroup property
The renderGroup should refer to a component featuring a customized GroupHeader element styled with styled.
...
renderGroup={(params) => (
<li key={params.key}>
<GroupHeader>{params.group}</GroupHeader>
<GroupItems>{params.children}</GroupItems>
</li>
)}
...
The First Group Header
By combining these three concepts, the firstLetter property and styling props from styled can be leveraged to identify the First Group Header. Modify the GroupHeader component definition in the MUI example as shown below:
const GroupHeader = styled('div')(({ theme, ...props }) => {
let isFirstGroup = sortedOptions[0].firstLetter === props.children;
return {
position: 'sticky',
top: '-8px',
height: isFirstGroup ? '100px' : 'inherit', // Sample adjustment for the First Group.
padding: '4px 10px',
color: theme.palette.primary.main,
backgroundColor:
theme.palette.mode === 'light'
? lighten(theme.palette.primary.light, 0.85)
: darken(theme.palette.primary.main, 0.8),
}
});
This approach works due to the specific signature of the Autocomplete renderGroup callback function:
Signature:
function( params: AutocompleteRenderGroupParams ) => ReactNode
The Autocomplete provides params to the callback, representing the group to render:
let params = {
group: a string indicating a group name
children: a collection of list items belonging to the group
};
When renderGroup iterates through the elements in the array passed to the groupBy property, it supplies the renderGroup callback with a param object resembling this structure (assuming a group name starts with the letter 'A'):
param = {
group: 'A',
children: ...
};
Hence, the line
<GroupHeader>{params.group}</GroupHeader>
actually renders
<GroupHeader>{'A'}</GroupHeader>
.
Since 'A' is the child of GroupHeader, we can utilize
let isFirstGroup = sortedOptions[0].firstLetter === props.children;
to extract
'A' (
props.children === 'A') and compare it with the firstLetter property of the initial element in the
sortedOptions array.