Hermes Worker


Hermes Worker is a small library made to simplify WebWorker usage.

In a nutshell, it is a tool which can be used by a web page for computation and which returns the result when it is ready.

Install

Add the package to your project as a dependency:

npm install hermes-worker

Please note that current version does not work with NodeJS (Blob not available)

Example

``js
const HermesWorker = require("hermes-worker");

// Code to be run on worker side
const workerFunction = () => {
// Expose a function
hermes.on("add", (a, b) => {
return a + b;
});

// Finish worker initialization
hermes.ready();
}

// Create a worker
const hermes = new HermesWorker(workerFunction, {});

// Call function "add" and retrieve answer
hermes.call("add", [1, 2]).then(result => {
console.log(result); // result === 3
});
`

Features

- Simple communication between page and worker
- Instantiate worker from url or function
- Multiple instances of the same worker
- Single external scripts import shared between worker instances
- Serialize data between page and worker
- Add custom serializers

Usage

$3

script.js
`js
const HermesWorker = require("hermes-worker");

// Create a worker
const hermes = new HermesWorker("workerFile.js", {});

// Call function "add" and retrieve answer
hermes.call("add", [1, 2]).then(result => {
console.log(result); // result === 3
});
`
workerFile.js
`js
// Code to be run in worker side
// Expose a function
hermes.on("add", (a, b) => {
return a + b;
});

// Finish worker initialization
hermes.ready();
`

$3

`js
const HermesWorker = require("hermes-worker");

const workerFunction = () => {
const fibo = (n) => {
if (n === 0 || n === 1) {
return 1;
}
return fibo(n - 1) + fibo(n - 2);
}
hermes.on("fibo", (n) => fibo(n));
hermes.on("hello", () => {
console.log(Hello world from instance ${hermes.config.threadInstance})
})
hermes.ready();
}

// Create two workers with same code
const hermes = new HermesWorker(workerFunction, {
threadInstances: 2
});

// Run by first instance
hermes.call("fibo", [12]);

// Run by second instance
hermes.call("fibo", [34]);

hermes.call("hello"); // Output => "Hello world from instance 0"
hermes.call("hello"); // Output => "Hello world from instance 1"
`

$3

`js
const HermesWorker = require("hermes-worker");

const workerFunction = () => {
/ HERE BABYLON IS DEFINED /
hermes.on("length", (x, y) => {
return new BABYLON.Vector2(x, y).length();
});

hermes.ready();
};

// Create a worker
const hermes = new HermesWorker(workerFunction, {
scripts: [
"https://cdn.babylonjs.com/babylon.js"
]
});

hermes.call("length", [1, 0]).then(result => {
console.log(result); // result === 1
});
`

$3

Data passed between page and worker are serialized to avoid data loss.

List of handled types:
- Number
- Number[]
- String
- String[]
- Object
- Object[]
- Error
- TypedArray
- ImageData
- ArrayBuffer
- DataView

You can also create your own serializer

`js
const HermesWorker = require("hermes-worker");

// Caution: Hermes only reads serialize and unserialize keys
const BabylonSerializer = {
serialize: (args) => {
return args.map((arg) => {
if (arg instanceof BABYLON.Vector2) {
return {
_x: arg.x,
_y: arg.y,
__type__: "BABYLON.Vector2",
};
}
return arg;
});
},
unserialize: (args) => {
return args => args.map((arg) => {
if (arg.__type__ === "BABYLON.Vector2") {
return new BABYLON.Vector2(arg._x, arg._y);
}
return arg;
});
},
};

const workerFunction = () => {
hermes.on("length", (vector) => {
return vector.length();
});

hermes.ready();
};

const hermes = new HermesWorker(workerFunction, {
scripts: ["https://cdn.babylonjs.com/babylon.js"],
serializers: [
BabylonSerializer,
],
});

hermes.call("length", [new BABYLON.Vector2(2, 0)]).then(result => {
console.log(result); // result === 2
});
``

$3

* v1.0.0: Initial release
* v1.0.1: Add latest file in npm
* v1.1.0:
* Clean Serializer
* Fix bug transferable
* v1.2.0:
* Throw error on unsupported type are send
* Add possibility to use offscreencanvas