Method traverseBreadthFirst

lib/graph/ProjectGraph.js:390–434

* Visit every project in the graph that can be reached by the given entry project exactly once. * The entry project defaults to the root project. * In case a cycle is detected, an error is thrown * * @public * @param {string} [startName] Name of the project to start the traversal at. Defau

(startName, callback)

	 * @param {@ui5/project/graph/ProjectGraph~traversalCallback} callback Will be called
	 */
	async traverseBreadthFirst(startName, callback) {
		if (!callback) {
			// Default optional first parameter
			callback = startName;
			startName = this._rootProjectName;
		}

		if (!this.getProject(startName)) {
			throw new Error(`Failed to start graph traversal: Could not find project ${startName} in project graph`);
		}

		const queue = [{
			projectNames: [startName],
			ancestors: []
		}];

		const visited = Object.create(null);

		while (queue.length) {
			const {projectNames, ancestors} = queue.shift(); // Get and remove first entry from queue

			await Promise.all(projectNames.map(async (projectName) => {
				this._checkCycle(ancestors, projectName);

				if (visited[projectName]) {
					return visited[projectName];
				}

				return visited[projectName] = (async () => {
					const newAncestors = [...ancestors, projectName];
					const dependencies = this.getDependencies(projectName);

					queue.push({
						projectNames: dependencies,
						ancestors: newAncestors
					});

					await callback({
						project: this.getProject(projectName),
						dependencies
					});
				})();
			}));
		}
	}

	/**
	 * Visit every project in the graph that can be reached by the given entry project exactly once.