icodeforlove/task.js

const functionToObjectURL = require('./functionToObjectURL');
const GeneralWorker = require('../GeneralWorker');

class WebWorker extends GeneralWorker {
    constructor ($config) {
        super(...arguments);

        this._worker = new Worker(functionToObjectURL(this.WORKER_SOURCE));
        this._worker.addEventListener('message', this._onMessage);

        if (this._debug) {
            this._log({
                action: 'initialized'
            });
        }
    }

    WORKER_SOURCE = `function () {
        let global = new Proxy(
          {},
          {
            set: (obj, prop, newval) => (self[prop] = newval)
          }
        );

        onmessage = function (event) {
            var message = event.data;

            var args = Object.keys(message).filter(function (key) {
                return key.match(/^argument/);
            }).sort(function (a, b) {
                return parseInt(a.slice(8), 10) - parseInt(b.slice(8), 10);
            }).map(function (key) {
                return message[key];
            });

            try {
                var result = eval('(' + message.func + ')').apply(null, args);

                if (result && result.then && result.catch && result.finally) {
                    result.then(result => {
                        self.postMessage({id: message.id, result: result});
                    }).catch(error => {
                        self.postMessage({id: message.id, error: error.stack});
                    });
                } else {
                    self.postMessage({id: message.id, result: result});
                }
            } catch (error) {
                self.postMessage({id: message.id, error: error.stack});
            }
        }
    }`;

    _onMessage = (event) => {
        let message = event.data;
        this.handleWorkerMessage(message);
    }

    postMessage = (message, transferables) => {
        if (this._debug) {
            this._log({
                taskId: message.id,
                action: 'send_task_to_actual_worker',
                message: `sending taskId(${message.id}) to worker process`
            });
        }
        this._worker.postMessage(message, transferables);
    }

    terminate = () => {
        if (this._debug) {
            this._log({
                message: 'terminated'
            });
        }
        this._worker.terminate();
    }
}

module.exports = WebWorker;