comlink/messagechanneladapter.js

/**
 * Copyright 2017 Google Inc. All Rights Reserved.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *     http://www.apache.org/licenses/LICENSE-2.0
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
export function wrap(smc, id = null) {
    const { port1, port2 } = new MessageChannel();
    hookup(port2, smc, id);
    return port1;
}
function hookup(internalPort, smc, id = null) {
    internalPort.onmessage = (event) => {
        if (!id)
            id = generateUID();
        const msg = event.data;
        const messageChannels = Array.from(findMessageChannels(event.data));
        for (const messageChannel of messageChannels) {
            const id = generateUID();
            const channel = replaceProperty(msg, messageChannel, id);
            hookup(channel, smc, id);
        }
        const payload = JSON.stringify({ id, msg, messageChannels });
        smc.send(payload);
    };
    smc.addEventListener("message", (event) => {
        let data = {};
        try {
            data = JSON.parse(event.data);
        }
        catch (e) {
            return;
        }
        if (!id)
            id = data.id;
        if (id !== data.id)
            return;
        const mcs = data.messageChannels.map(messageChannel => {
            const id = messageChannel.reduce((obj, key) => obj[key], data.msg);
            const port = wrap(smc, id);
            replaceProperty(data.msg, messageChannel, port);
            return port;
        });
        internalPort.postMessage(data.msg, mcs);
    });
}
function replaceProperty(obj, path, newVal) {
    for (const key of path.slice(0, -1))
        obj = obj[key];
    const key = path[path.length - 1];
    const orig = obj[key];
    obj[key] = newVal;
    return orig;
}
function* findMessageChannels(obj, path = []) {
    if (!obj)
        return;
    if (typeof obj === "string")
        return;
    if (obj instanceof MessagePort) {
        yield path.slice();
        return;
    }
    for (const key of Object.keys(obj)) {
        path.push(key);
        yield* findMessageChannels(obj[key], path);
        path.pop();
    }
}
function hex4() {
    return Math.floor((1 + Math.random()) * 0x10000)
        .toString(16)
        .substring(1);
}
const bits = 128;
function generateUID() {
    return new Array(bits / 16)
        .fill(0)
        .map(_ => hex4())
        .join("");
}