Implementing Incremental Compilation in an Angular Component

Incremental compilation in Angular significantly speeds up build times, especially for large projects, by only recompiling changed files. This challenge focuses on creating a simplified, demonstrable version of incremental compilation for a single Angular component, allowing you to understand the core principles involved. You'll be simulating the process of identifying changed files and only compiling those.

Problem Description

You are tasked with creating a rudimentary incremental compilation system for a single Angular component. The system should take a list of files representing the component's template, styles, and TypeScript code, along with a list of files that have been modified since the last compilation. The system should then determine which files need to be recompiled and return a list of those files. This simulates the core logic of Angular's incremental compilation.

Key Requirements:

• File Types: The system must recognize and handle the following file types: .ts (TypeScript), .html (Template), and .css (Styles).
• Change Detection: The system must accurately identify files that have been modified based on the provided list of changed files.
• Component Association: The system must correctly associate template and style files with their corresponding component TypeScript file. Assume a naming convention: component-name.ts, component-name.html, and component-name.css.
• Output: The system should return an array of file paths that need to be recompiled.

Expected Behavior:

Given a set of component files and a list of modified files, the system should return only the files that belong to the component and are present in the modified files list.

Edge Cases to Consider:

• What happens if a modified file is not part of the component? (It should be ignored).
• What happens if a component file is modified, but none of its associated template or style files are? (Only the component file should be returned).
• What happens if multiple files associated with the component are modified? (All modified files should be returned).
• What happens if a file is modified that doesn't follow the naming convention? (It should be ignored).

Examples

Example 1:

Input:
componentFiles = ["my-component.ts", "my-component.html", "my-component.css"]
modifiedFiles = ["my-component.ts", "some-other-file.js", "my-component.html"]
Output: ["my-component.ts", "my-component.html"]
Explanation: Both "my-component.ts" and "my-component.html" are part of the component and are present in the modifiedFiles list. "some-other-file.js" is ignored.

Example 2:

Input:
componentFiles = ["product-list.ts", "product-list.html", "product-list.css"]
modifiedFiles = ["product-list.ts"]
Output: ["product-list.ts"]
Explanation: Only "product-list.ts" is modified and belongs to the component.

Example 3:

Input:
componentFiles = ["user-profile.ts", "user-profile.html", "user-profile.css"]
modifiedFiles = ["another-component.ts", "some-random.txt"]
Output: []
Explanation: None of the modified files belong to the component.

Constraints

• componentFiles will always be an array of strings.
• modifiedFiles will always be an array of strings.
• File paths are case-sensitive.
• The component name is assumed to be the base name of the .ts file (e.g., "my-component.ts" has component name "my-component").
• Performance is not a primary concern for this simplified challenge. Focus on correctness and clarity.

Notes

• Consider using string manipulation techniques (e.g., split, substring) to extract component names from file paths.
• Think about how to efficiently check if a file belongs to the component.
• This is a simplified simulation. A real-world incremental compilation system would involve more complex dependency analysis and caching mechanisms.
• The goal is to demonstrate the logic of identifying changed files, not to build a fully functional Angular compiler.

function incrementalCompile(componentFiles: string[], modifiedFiles: string[]): string[] {
  // Your code here
  return [];
}