@reclaimprotocol/tls/lib/utils/parse-alert.js

WebCrypto Based Cross Platform TLS

import { ALERT_DESCRIPTION, ALERT_LEVEL } from "./constants.js";
import { uint8ArrayToDataView } from "./generics.js";
const ALERT_LEVEL_ENTRIES = Object
    .entries(ALERT_LEVEL);
const ALERT_DESCRIPTION_ENTRIES = Object
    .entries(ALERT_DESCRIPTION);
/**
 * Parse a TLS alert message
 */
export function parseTlsAlert(buffer) {
    const view = uint8ArrayToDataView(buffer);
    const level = view.getUint8(0);
    const description = view.getUint8(1);
    const levelStr = ALERT_LEVEL_ENTRIES
        .find(([, value]) => value === level)?.[0];
    if (!levelStr) {
        throw new Error(`Unknown alert level ${level}`);
    }
    const descriptionStr = ALERT_DESCRIPTION_ENTRIES
        .find(([, value]) => value === description)?.[0];
    if (!descriptionStr) {
        throw new Error(`Unknown alert description ${description}`);
    }
    return {
        level: levelStr,
        description: descriptionStr
    };
}