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import type { LoadingSkeletonProps, SkeletonVariant } from '../../types/componentPropExports';
/**
* Configuration structure for skeleton variants
*
* Defines the rendering configuration for each skeleton variant including
* accessibility attributes and the render function that produces the skeleton DOM.
*
* @property ariaLabel - ARIA label for screen readers describing what's loading
* @property srText - Screen reader text announced when skeleton is rendered
* @property render - Function that generates the skeleton DOM elements
*/
interface SkeletonVariantConfig {
ariaLabel: string;
srText: string;
render: (skeletonClasses: string) => React.ReactNode;
}
/**
* Loading skeleton component for better perceived performance
*
* ## Business Perspective
*
* Improves perceived performance by showing content placeholders while
* data loads, making the application feel more responsive and reducing
* user anxiety during loading operations. 📊
*
* ## Technical Perspective
*
* Provides animated placeholder content that mimics the structure of
* the actual content being loaded. Uses CSS animations for smooth
* skeleton shimmer effect. Supports multiple variants for different
* widget layouts.
*
* @example
* ```tsx
* // Default 3-line skeleton
* <LoadingSkeleton />
*
* // Custom number of lines
* <LoadingSkeleton lines={5} />
*
* // Summary widget skeleton
* <LoadingSkeleton variant="summary" />
*
* // Chart widget skeleton
* <LoadingSkeleton variant="chart" />
*
* // Metrics widget skeleton
* <LoadingSkeleton variant="metrics" />
* ```
*/
export const LoadingSkeleton: React.FC<LoadingSkeletonProps> = ({
lines = 3,
variant = 'default',
testId = 'loading-skeleton',
className = ''
}) => {
const baseClasses = 'animate-pulse';
const skeletonClasses = 'bg-gray-200 dark:bg-gray-700 rounded';
// Configuration map for each variant
const variantConfigs: Record<SkeletonVariant, SkeletonVariantConfig> = {
default: {
ariaLabel: 'Loading content',
srText: 'Loading...',
render: (classes) => (
<>
{Array.from({ length: lines }).map((_, i) => (
<div
key={`skeleton-line-${i}`}
className={`h-4 ${classes}`}
data-testid={`${testId}-line-${i}`}
aria-hidden="true"
/>
))}
</>
)
},
summary: {
ariaLabel: 'Loading summary',
srText: 'Loading summary...',
render: (classes) => (
<>
<div className={`h-8 ${classes} w-3/4`} aria-hidden="true" />
<div className={`h-24 ${classes}`} aria-hidden="true" />
<div className="grid grid-cols-1 sm:grid-cols-3 gap-4">
{['summary-metric-1', 'summary-metric-2', 'summary-metric-3'].map((key) => (
<div key={key} className={`h-20 ${classes}`} aria-hidden="true" />
))}
</div>
</>
)
},
chart: {
ariaLabel: 'Loading chart',
srText: 'Loading chart...',
render: (classes) => (
<>
<div className={`h-6 ${classes} w-1/2`} aria-hidden="true" />
<div className={`h-64 ${classes}`} aria-hidden="true" />
<div className="flex justify-between gap-4">
{['legend-1', 'legend-2', 'legend-3', 'legend-4'].map((key) => (
<div key={key} className={`h-4 w-16 ${classes}`} aria-hidden="true" />
))}
</div>
</>
)
},
list: {
ariaLabel: 'Loading list',
srText: 'Loading list...',
render: (classes) => (
<>
{['list-item-1', 'list-item-2', 'list-item-3', 'list-item-4', 'list-item-5'].map((key) => (
<div key={key} className="flex items-center space-x-4">
<div className={`h-10 w-10 ${classes} rounded-full`} aria-hidden="true" />
<div className="flex-1 space-y-2">
<div className={`h-4 ${classes} w-3/4`} aria-hidden="true" />
<div className={`h-3 ${classes} w-1/2`} aria-hidden="true" />
</div>
</div>
))}
</>
)
},
metrics: {
ariaLabel: 'Loading metrics',
srText: 'Loading metrics...',
render: (classes) => (
<div className="grid grid-cols-1 sm:grid-cols-2 lg:grid-cols-4 gap-4">
{['metric-1', 'metric-2', 'metric-3', 'metric-4'].map((key) => (
<div key={key} className="space-y-3">
<div className={`h-4 ${classes} w-2/3`} aria-hidden="true" />
<div className={`h-8 ${classes}`} aria-hidden="true" />
<div className={`h-3 ${classes} w-1/2`} aria-hidden="true" />
</div>
))}
</div>
)
},
tabs: {
ariaLabel: 'Loading tabs',
srText: 'Loading tabs...',
render: (classes) => (
<>
<div className="flex space-x-2 border-b border-gray-200 dark:border-gray-700">
{['tab-1', 'tab-2', 'tab-3', 'tab-4'].map((key) => (
<div key={key} className={`h-10 w-24 ${classes} mb-[-1px]`} aria-hidden="true" />
))}
</div>
<div className="space-y-3">
<div className={`h-6 ${classes} w-3/4`} aria-hidden="true" />
<div className={`h-32 ${classes}`} aria-hidden="true" />
<div className={`h-4 ${classes} w-5/6`} aria-hidden="true" />
<div className={`h-4 ${classes} w-4/6`} aria-hidden="true" />
</div>
</>
)
}
};
// Get the configuration for the current variant, fallback to default
const config = variantConfigs[variant] || variantConfigs.default;
// Explicit spacing configuration per variant for maintainability
const spaceClassMap: Record<SkeletonVariant, string> = {
default: 'space-y-4',
summary: 'space-y-4',
chart: 'space-y-4',
tabs: 'space-y-4',
list: 'space-y-3',
metrics: ''
};
const spaceClass = spaceClassMap[variant] || spaceClassMap.default;
return (
<div
className={`${baseClasses} ${spaceClass} ${className}`}
data-testid={testId}
role="status"
aria-label={config.ariaLabel}
>
{config.render(skeletonClasses)}
<span className="sr-only">{config.srText}</span>
</div>
);
};
export default LoadingSkeleton;
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