Support get_type_description service via parameter

[minggangw]

This PR adds support for starting the type description service via a configurable parameter and includes a new test case to verify that configuration.

• Added a new test case in test/test-type-description-service.js to check the parameter configuration.
• Updated lib/type_description_service.js to declare and retrieve the "start_type_description_service" parameter and conditionally start the service.

Fix: #1161

[Copilot]

Pull Request Overview

Adds a new ROS2 parameter to control whether the type description service is started and includes a test to verify that parameter is registered.

• Declare and retrieve a start_type_description_service boolean parameter in TypeDescriptionService and conditionally start the service.
• Add a test that shells out to ros2 param list to confirm the new parameter is present on the node.

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

File	Description
test/test-type-description-service.js	Import exec and add test to verify start_type_description_service appears in parameter list.
lib/type_description_service.js	Declare/retrieve the new parameter and update start() to respect the parameter’s value.

Comments suppressed due to low confidence (2)

lib/type_description_service.js:32

• [nitpick] Add a note in the class-level JSDoc explaining the new 'start_type_description_service' parameter and its default behavior.

// This class is used to create a TypeDescriptionService which can be used to

test/test-type-description-service.js:78

• Add a complementary test case to verify that when start_type_description_service is set to false, the service does not start.

  it('Test type description service configured by parameter', function (done) {

[Copilot]

[nitpick] Consider extracting the parameter name 'start_type_description_service' into a top-level constant to avoid duplication and reduce risk of typos.

Suggested change

	const startTypeDescriptionServiceParam = 'start_type_description_service';
	if (!node.hasParameter(startTypeDescriptionServiceParam)) {
	node.declareParameter(
	new Parameter(
	startTypeDescriptionServiceParam,
	ParameterType.PARAMETER_BOOL,
	true
	),
	new ParameterDescriptor(
	startTypeDescriptionServiceParam,
	ParameterType.PARAMETER_BOOL,
	'If enabled, start the ~/get_type_description service.',
	true
	)
	);
	}
	const param = node.getParameter(startTypeDescriptionServiceParam);
	if (!node.hasParameter(START_TYPE_DESCRIPTION_SERVICE_PARAM)) {
	node.declareParameter(
	new Parameter(
	START_TYPE_DESCRIPTION_SERVICE_PARAM,
	ParameterType.PARAMETER_BOOL,
	true
	),
	new ParameterDescriptor(
	START_TYPE_DESCRIPTION_SERVICE_PARAM,
	ParameterType.PARAMETER_BOOL,
	'If enabled, start the ~/get_type_description service.',
	true
	)
	);
	}
	const param = node.getParameter(START_TYPE_DESCRIPTION_SERVICE_PARAM);

[Copilot]

Shelling out to ros2 in tests can be brittle; consider using the rclnodejs Node API to list or get parameters directly in code for a more reliable test.

Suggested change

	exec(
	'ros2 param list /test_type_description_service',
	(error, stdout, stderr) => {
	if (error || stderr) {
	done(
	new Error(
	'Test type description service configured by parameter failed.'
	)
	);
	}
	if (stdout.includes('start_type_description_service')) {
	done();
	} else {
	done(
	new Error("'start_type_description_service' not found in stdout.")
	);
	}
	}
	);
	const parameterName = 'start_type_description_service';
	const parameters = node.getParameters([parameterName]);
	if (parameters[parameterName] !== undefined) {
	done();
	} else {
	done(
	new Error(`'${parameterName}' not found in node parameters.`)
	);
	}

[Copilot]

[nitpick] Currently the test fails on any stderr output; consider only failing on a non-zero exit code and logging stderr to avoid false negatives from warnings.

Suggested change

	if (error || stderr) {
	done(
	new Error(
	'Test type description service configured by parameter failed.'
	)
	);
	}
	if (error) {
	done(
	new Error(
	`Test type description service configured by parameter failed with error: ${error.message}`
	)
	);
	return;
	}
	if (stderr) {
	console.warn(`Warning: stderr output detected: ${stderr}`);
	}

[coveralls]

coverage: 84.711% (+0.09%) from 84.625%
when pulling 341f936 on minggangw:fix-1161
into b3cf4a7 on RobotWebTools:develop.