workers | API Reference | ArcGIS Maps SDK for JavaScript 4.33

See also

ES modules custom workers sample

Method Overview

Name	Return Type	Summary	Object
	Promise<Connection>	Opens a connection to workers and loads a script with the workers framework.	workers

Method Details

open Method open(modulePath, options){Promise<Connection>}

Opens a connection to workers and loads a script with the workers framework.

Parameters

Specification

modulePath String

A fully qualified URL to a script to execute with the workers framework.

options Object

optional

Worker options. See properties below for object specifications.

Specification

client Object

optional

The objects defining the API accessible from the module.

strategy String

optional

Default Value: distributed

Indicates how to load the module. See the table below for a list of possible values.

Possible Value	Description
distributed	The module is loaded in each available worker. Each call to Connection.invoke will be targeting an available worker. Use this strategy if the module doesn't maintain information between invocations (stateless).
dedicated	The module is loaded in one worker. Each call to Connection.invoke will be targeting a same worker. Use this strategy if the module maintains information from previous invocations or communication between main and worker threads needs to be stateful.
local	The module is loaded in the main thread. Use this strategy when using the worker framework API while disabling the use of workers.

Possible Values:"distributed"|"dedicated"|"local"

signal AbortSignal|null|undefined

optional

AbortSignal allows for cancelable asynchronous job. If canceled, the promise will be rejected with an error named AbortError. See also AbortController.

Returns

Type	Description
Promise<Connection>	Resolves to an instance of Connection.

See also

Connection

Examples

// Set the path for the worker's AMD loader configuration
// to a folder called workersFolder.
esriConfig.workers.loaderConfig = {
 paths: {
   myWorkers: new URL("./workersFolder", document.baseURI).href
 }
};

// load myWorkers/Calculator.js in the workers framework
// and invoke its "getMaxNumber" method
workers.open("myWorkers/Calculator")
  .then((connection) => {
    return connection.invoke("getMaxNumber", [0, 1, 2, 3, 4]);
  })
  .then((result) => {
    console.log(result);
  });

//*********************************************************
// module: workerFolder/Calculator.js
//*********************************************************
define([], () => {
  return {
    // this function can be invoked from the main thread
    getMaxNumber: function (number) {
      return Math.max.apply(null, numbers);
    }
  };
});

// Load workerScripts/TimeOfTheDay.js in the workers framework
// We define an API accessible from the module
workers.open(new URL("./workerScripts/TimeOfDay.js", document.baseURI).href, {
  client: {
    getCurrentTime: function() {
      return Date.now();
    }
  }
})
  .then((connection) => {
    return connection.invoke("timeOfTheDay");
  })
  .then((result) => {
    console.log(result);
  });

//*********************************************************
// module: workerScripts/TimeOfTheDay.js
//*********************************************************

define([], () => {

  return {
    timeOfTheDay: function(noArgs, remoteClient) {
      // call back the main thread to get the current time over there.
      return remoteClient.invoke("getCurrentTime")
        .then((time) => {
          return "The time is " + time;
        });
    }
  };
});