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<h1>[name]</h1>
<p class="desc">
This article shows how to get three.js into a [link:https://nodejs.org/en/ node.js] environment so that you
can execute automated tests. Tests can be run on the command line, or by automated
CI tools like [link:https://travis-ci.org/ Travis].
</p>
<h2>The short version</h2>
<p>
If you're comfortable with node and npm,
<code>
$ npm install three --save-dev
</code>
and add
<code>
const THREE = require('three');
</code>
to your test.
</p>
<h2>Create a testable project from scratch</h2>
<p>
If you're not familiar with these tools, here's a quick guide (for linux, the installation process
will be slightly different using windows, but the NPM commands are identical).
</p>
<h3>Basic setup</h3>
<div>
<ol>
<li>
Install [link:https://www.npmjs.org/ npm] and nodejs. The shortest path typically looks something like
<code>
$ sudo apt-get install -y npm nodejs-legacy
# fix any problems with SSL in the default registry URL
$ npm config set registry http://registry.npmjs.org/
</code>
</li>
<li>
Make a new project directory
<code>
$ mkdir test-example; cd test-example
</code>
</li>
<li>
Ask npm to create a new project file for you:
<code>
$ npm init
</code>
and accept all defaults by hitting Enter on all the prompts.
This will create package.json.
</li><br />
<li>
Try and start the test feature with
<code>
$ npm test
</code>
This will fail, which is expected.
If you look in the package.json, the definition of the test script is
<code>
"test": "echo \"Error: no test specified\" && exit 1"
</code>
</li>
</ol>
</div>
<h2>Add mocha</h2>
<div>
We're going to use [link:https://mochajs.org/ mocha].
<ol>
<li>
Install mocha with
<code>
$ npm install mocha --save-dev
</code>
Notice that node_modules/ is created and your dependencies appear in there.
Also notice that your package.json has been updated: the property devDependencies
is added and updated by the use of --save-dev.
</li><br />
<li>
Edit package.json to use mocha for testing. When test is invoked, we just want to run
mocha and specify a verbose reporter. By default this will run anything in test/
(not having directory test/ can run into npm ERR!, create it by mkdir test)
<code>
"test": "mocha --reporter list"
</code>
</li>
<li>
Rerun the test with
<code>
$ npm test
</code>
This should now succeed, reporting 0 passing (1ms)
or similar.
</li>
</ol>
</div>
<h2>Add three.js</h2>
<div>
<ol>
<li>
Let's pull in our three.js dependency with
<code>
$ npm install three --save-dev
</code>
<ul>
<li>
If you need a different three version, use
<code>
$ npm show three versions
</code>
to see
what's available. To tell npm the right one, use
<code>
$ npm install three@0.84.0 --save
</code>
(0.84.0 in this example). --save makes this a dependency of this project, rather than
dev dependency. See the docs [link:https://docs.npmjs.com/cli/v8/configuring-npm/package-json here] for more info.
</li>
</ul>
</li>
<li>
Mocha will look for tests in test/, so let's
<code>
$ mkdir test
</code>
</li>
<li>
Finally we actually need a JS test to run. Let's add a simple test that will verify that
the three.js object is available and working. Create test/verify-three.js containing:
<code>
const THREE = require('three');
const assert = require('assert');
describe('The THREE object', function() {
it('should have a defined BasicShadowMap constant', function() {
assert.notEqual('undefined', THREE.BasicShadowMap);
}),
it('should be able to construct a Vector3 with default of x=0', function() {
const vec3 = new THREE.Vector3();
assert.equal(0, vec3.x);
})
})
</code>
</li>
<li>
Finally let's test again with $ npm test. This should run the tests above and succeed,
showing something like:
<code>
The THREE object should have a defined BasicShadowMap constant: 0ms
The THREE object should be able to construct a Vector3 with default of x=0: 0ms
2 passing (8ms)
</code>
</li>
</ol>
</div>
<h2>Add your own code</h2>
<div>
You need to do three things:
<ol>
<li>
Write a test for the expected behaviour of your code, and place it under test/.
[link:https://github.com/air/encounter/blob/master/test/Physics-test.js Here] is an example from a real project.
</li>
<li>
Export your functional code in such a way that nodejs can see it, for use in conjunction with require.
See it [link:https://github.com/air/encounter/blob/master/js/Physics.js here].
</li>
<li>
Require your code into the test file, in the same way we did a require('three') in the example above.
</li>
</ol>
<p>
Items 2 and 3 will vary depending on how you manage your code. In the example of Physics.js
given above, the export part is right at the end. We assign an object to module.exports:
</p>
<code>
//=============================================================================
// make available in nodejs
//=============================================================================
if (typeof exports !== 'undefined')
{
module.exports = Physics;
}
</code>
</div>
<h2>Dealing with dependencies</h2>
<div>
<p>
If you're already using something clever like require.js or browserify, skip this part.
</p>
<p>
Typically a three.js project is going to run in the browser. Module loading is hence done by
the browser executing a bunch of script tags. Your individual files don't have to worry
about dependencies. In a nodejs context however, there is no index.html binding everything
together, so you have to be explicit.
</p>
<p>
If you're exporting a module that depends on other files, you're going to have to tell node to load them.
Here is one approach:
</p>
<ol>
<li>
At the start of your module, check to see if you're in a nodejs environment.
</li>
<li>
If so, explicitly declare your dependencies.
</li>
<li>
If not, you're probably in a browser so you don't need to do anything else.
</li>
</ol>
Example code from Physics.js:
<code>
//=============================================================================
// setup for server-side testing
//=============================================================================
if (typeof require === 'function') // test for nodejs environment
{
const THREE = require('three');
const MY3 = require('./MY3.js');
}
</code>
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