matrix-js-sdk/examples/crypto-browser/olm-device-export-import.js

if (!Olm) {
    console.error("global.Olm does not seem to be present." + " Did you forget to add olm in the lib/ directory?");
}

const BASE_URL = "http://localhost:8008";
const ROOM_CRYPTO_CONFIG = { algorithm: "m.megolm.v1.aes-sha2" };
const PASSWORD = "password";

// useful to create new usernames
window.randomHex = () => Math.floor(Math.random() * 10 ** 6).toString(16);

window.newMatrixClient = async function (username) {
    const registrationClient = matrixcs.createClient(BASE_URL);

    const userRegisterResult = await registrationClient.register(username, PASSWORD, null, { type: "m.login.dummy" });

    const matrixClient = matrixcs.createClient({
        baseUrl: BASE_URL,
        userId: userRegisterResult.user_id,
        accessToken: userRegisterResult.access_token,
        deviceId: userRegisterResult.device_id,
        sessionStore: new matrixcs.WebStorageSessionStore(window.localStorage),
        cryptoStore: new matrixcs.MemoryCryptoStore(),
    });

    extendMatrixClient(matrixClient);

    await matrixClient.initCrypto();
    await matrixClient.startClient();
    return matrixClient;
};

window.importMatrixClient = async function (exportedDevice, accessToken) {
    const matrixClient = matrixcs.createClient({
        baseUrl: BASE_URL,
        deviceToImport: exportedDevice,
        accessToken,
        sessionStore: new matrixcs.WebStorageSessionStore(window.localStorage),
        cryptoStore: new matrixcs.MemoryCryptoStore(),
    });

    extendMatrixClient(matrixClient);

    await matrixClient.initCrypto();
    await matrixClient.startClient();
    return matrixClient;
};

function extendMatrixClient(matrixClient) {
    // automatic join
    matrixClient.on("RoomMember.membership", async (event, member) => {
        if (member.membership === "invite" && member.userId === matrixClient.getUserId()) {
            await matrixClient.joinRoom(member.roomId);
            // setting up of room encryption seems to be triggered automatically
            // but if we don't wait for it the first messages we send are unencrypted
            await matrixClient.setRoomEncryption(member.roomId, { algorithm: "m.megolm.v1.aes-sha2" });
        }
    });

    matrixClient.onDecryptedMessage = (message) => {
        console.log("Got encrypted message: ", message);
    };

    matrixClient.on("Event.decrypted", (event) => {
        if (event.getType() === "m.room.message") {
            matrixClient.onDecryptedMessage(event.getContent().body);
        } else {
            console.log("decrypted an event of type", event.getType());
            console.log(event);
        }
    });

    matrixClient.createEncryptedRoom = async function (usersToInvite) {
        const { room_id: roomId } = await this.createRoom({
            visibility: "private",
            invite: usersToInvite,
        });

        // matrixClient.setRoomEncryption() only updates local state
        // but does not send anything to the server
        // (see https://github.com/matrix-org/matrix-js-sdk/issues/905)
        // so we do it ourselves with 'sendStateEvent'
        await this.sendStateEvent(roomId, "m.room.encryption", ROOM_CRYPTO_CONFIG);
        await this.setRoomEncryption(roomId, ROOM_CRYPTO_CONFIG);

        // Marking all devices as verified
        let room = this.getRoom(roomId);
        let members = (await room.getEncryptionTargetMembers()).map((x) => x["userId"]);
        let memberkeys = await this.downloadKeys(members);
        for (const userId in memberkeys) {
            for (const deviceId in memberkeys[userId]) {
                await this.setDeviceVerified(userId, deviceId);
            }
        }

        return roomId;
    };

    matrixClient.sendTextMessage = async function (message, roomId) {
        return matrixClient.sendMessage(roomId, {
            body: message,
            msgtype: "m.text",
        });
    };
}