iconify/packages/utils/src/loader/loader.ts

import { getCustomIcon } from './custom';
import type { IconifyLoaderOptions } from './types';
import { searchForIcon } from './modern';

export async function loadIcon(
	collection: string,
	icon: string,
	options?: IconifyLoaderOptions
): Promise<string | undefined> {
	const custom = options?.customCollections?.[collection];

	if (custom) {
		if (typeof custom === 'function') {
			const result = await custom(icon);
			if (result) {
				if (typeof result === 'string') {
					return await getCustomIcon(() => result as string, collection, icon, options);
				}
				// if using dynamic import and requesting the json file
				// for example: carbon: () => import('@iconify-json/carbon/icons.json').then(i => i.default as any)
				if ('icons' in result) {
					// possible icon names
					const ids = [
						icon,
						icon.replace(/([a-z])([A-Z])/g, '$1-$2').toLowerCase(),
						icon.replace(/([a-z])(\d+)/g, '$1-$2'),
					];
					return await searchForIcon(result, collection, ids, options)
				}
			}
		} else {
			return await getCustomIcon(custom, collection, icon, options);
		}
	}

	return undefined;
}