TIL 2022-11-24 NextJS Image Optimizer
export function detectContentType(buffer: Buffer) { if ([0xff, 0xd8, 0xff].every((b, i) => buffer[i] === b)) { return JPEG } if ( [0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a].every( (b, i) => buffer[i] === b ) ) { return PNG } if ([0x47, 0x49, 0x46, 0x38].every((b, i) => buffer[i] === b)) { return GIF } if ( [0x52, 0x49, 0x46, 0x46, 0, 0, 0, 0, 0x57, 0x45, 0x42, 0x50].every( (b, i) => !b || ..