import { readFile } from "node:fs/promises";
/**
* Check if a string is already base64 encoded
* Supports both raw base64 and data URL format
*/
function isBase64(str: string): boolean {
// Check for data URL format (e.g., data:image/png;base64,...)
if (str.startsWith("data:") && str.includes(";base64,")) {
return true;
}
// Check if it looks like raw base64
// - Must be reasonably long (short strings are likely paths)
// - Must only contain valid base64 characters
// - Must have valid padding (0, 1, or 2 '=' characters at end)
if (str.length < 100) {
return false;
}
// Valid base64 pattern with proper padding
const base64Regex =
/^(?:[A-Za-z0-9+/]{4})*(?:[A-Za-z0-9+/]{2}==|[A-Za-z0-9+/]{3}=)?$/;
return base64Regex.test(str);
}
/**
* Convert an image path or base64 string to base64
* @param image - File path or base64-encoded string
* @returns Base64-encoded image data
* @throws Error if file cannot be read
*/
export async function toBase64(image: string): Promise<string> {
// If already base64, return as-is
if (isBase64(image)) {
return image;
}
// Try to read file and convert to base64
// Let readFile throw ENOENT if file doesn't exist (no need for separate existsSync check)
try {
const buffer = await readFile(image);
return buffer.toString("base64");
} catch (error) {
if (error instanceof Error && "code" in error && error.code === "ENOENT") {
throw new Error(`Image file not found: ${image}`);
}
throw error;
}
}
/**
* Process an array of images, converting file paths to base64
* @param images - Array of file paths or base64-encoded strings
* @returns Array of base64-encoded image data, or undefined if no images
*/
export async function processImages(
images: string[] | undefined
): Promise<string[] | undefined> {
if (!images || images.length === 0) {
return undefined;
}
return Promise.all(images.map(toBase64));
}
