export function makeImageProcessor()

in src/lib/server/endpoints/images.ts [41:89]
37 lines of code
11 McCabe index (conditional complexity)

export function makeImageProcessor<TMimeType extends string = string>(
	options: ImageProcessorOptions<TMimeType>
): ImageProcessor<TMimeType> {
	return async (file) => {
		const { supportedMimeTypes, preferredMimeType, maxSizeInMB, maxWidth, maxHeight } = options;
		const { mime, value } = file;

		const buffer = Buffer.from(value, "base64");
		let sharpInst = sharp(buffer);

		const metadata = await sharpInst.metadata();
		if (!metadata) throw Error("Failed to read image metadata");
		const { width, height } = metadata;
		if (width === undefined || height === undefined) throw Error("Failed to read image size");

		const tooLargeInSize = width > maxWidth || height > maxHeight;
		const tooLargeInBytes = buffer.byteLength > maxSizeInMB * 1000 * 1000;

		const outputMime = chooseMimeType(supportedMimeTypes, preferredMimeType, mime, {
			preferSizeReduction: tooLargeInBytes,
		});

		// Resize if necessary
		if (tooLargeInSize || tooLargeInBytes) {
			const size = chooseImageSize({
				mime: outputMime,
				width,
				height,
				maxWidth,
				maxHeight,
				maxSizeInMB,
			});
			if (size.width !== width || size.height !== height) {
				sharpInst = resizeImage(sharpInst, size.width, size.height);
			}
		}

		// Convert format if necessary
		// We always want to convert the image when the file was too large in bytes
		// so we can guarantee that ideal options are used, which are expected when
		// choosing the image size
		if (outputMime !== mime || tooLargeInBytes) {
			sharpInst = convertImage(sharpInst, outputMime);
		}

		const processedImage = await sharpInst.toBuffer();
		return { image: processedImage, mime: outputMime };
	};
}