packages/server/src/helpers/decodeClientDataJSON.ts


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import { isoBase64URL } from "./iso/index.ts";

/**
 * Decode an authenticator's base64url-encoded clientDataJSON to JSON
 */
export function decodeClientDataJSON(data: string): ClientDataJSON {
  const toString = isoBase64URL.toString(data);
  const clientData: ClientDataJSON = JSON.parse(toString);

  return _decodeClientDataJSONInternals.stubThis(clientData);
}

export type ClientDataJSON = {
  type: string;
  challenge: string;
  origin: string;
  crossOrigin?: boolean;
  tokenBinding?: {
    id?: string;
    status: "present" | "supported" | "not-supported";
  };
};

// Make it possible to stub the return value during testing
export const _decodeClientDataJSONInternals = {
  stubThis: (value: ClientDataJSON) => value,
};