Angular Version Migration Strategy Implementation

This challenge focuses on simulating and implementing a version migration strategy for an Angular application. In real-world Angular development, as new versions are released, applications often need to be updated to leverage new features, security patches, and performance improvements. This involves a structured process to ensure smooth transitions. You will implement a simplified version of this process, focusing on how different components might be affected by a "migration" event.

Problem Description

Your task is to create a system that simulates the process of migrating Angular components from one version to another. Imagine you have a collection of Angular components, each with a current version. When a migration occurs, specific components might need to be updated to a new version or might be retired entirely.

You will need to:

1. Represent Components: Define a way to represent an Angular component, including its name and current version.
2. Simulate Migration: Implement a function that takes a list of components and a migration plan. The migration plan will specify which components to update and to what new version, or if they should be removed.
3. Handle Different Migration Scenarios: The migration process should handle:
   • Updating existing components to a new version.
   • Removing components that are no longer supported.
   • Keeping components that are unaffected by the migration.
4. Return Migrated State: The function should return the new state of the component list after the migration has been applied.

Key Requirements:

• The solution must be implemented in TypeScript.
• You should define appropriate data structures to represent components and the migration plan.
• The migration function should be pure (no side effects on the original input data).

Expected Behavior:

• Given an initial list of components and a migration plan, the function should produce a new list reflecting the changes.
• Components not mentioned in the migration plan should remain in their original state.
• Components specified for update should have their version property changed.
• Components specified for removal should be absent from the resulting list.

Edge Cases to Consider:

• What if a component in the migration plan doesn't exist in the current list? (It should be ignored).
• What if the migration plan is empty? (The original list should be returned unchanged).
• What if a component is listed for removal and also for update? (Removal takes precedence).

Examples

Example 1: Basic Update and Keep

// Input Components
const initialComponents = [
  { name: "ButtonComponent", version: "1.0.0" },
  { name: "InputComponent", version: "2.1.0" },
  { name: "CardComponent", version: "3.0.0" },
];

// Input Migration Plan
const migrationPlan = {
  update: [
    { name: "ButtonComponent", newVersion: "1.1.0" },
    { name: "InputComponent", newVersion: "2.2.0" },
  ],
  remove: [],
};

// Expected Output Components
const expectedOutput = [
  { name: "ButtonComponent", version: "1.1.0" },
  { name: "InputComponent", version: "2.2.0" },
  { name: "CardComponent", version: "3.0.0" },
];

Explanation: ButtonComponent and InputComponent are updated to their new specified versions. CardComponent is not mentioned in the plan, so it remains unchanged.

Example 2: Removal and Update

// Input Components
const initialComponents = [
  { name: "UserList", version: "v1" },
  { name: "UserProfile", version: "v2" },
  { name: "AuthService", version: "v1" },
  { name: "Logger", version: "v3" },
];

// Input Migration Plan
const migrationPlan = {
  update: [
    { name: "UserProfile", newVersion: "v3" },
  ],
  remove: [
    "AuthService",
    "Logger",
  ],
};

// Expected Output Components
const expectedOutput = [
  { name: "UserList", version: "v1" },
  { name: "UserProfile", version: "v3" },
];

Explanation: UserProfile is updated to v3. AuthService and Logger are removed from the list. UserList is unaffected.

Example 3: Edge Case - Component Not Found in Plan

// Input Components
const initialComponents = [
  { name: "FeatureA", version: "1.0" },
  { name: "FeatureB", version: "1.2" },
];

// Input Migration Plan
const migrationPlan = {
  update: [
    { name: "NonExistentComponent", newVersion: "2.0" }, // This component is not in initialComponents
  ],
  remove: [],
};

// Expected Output Components
const expectedOutput = [
  { name: "FeatureA", version: "1.0" },
  { name: "FeatureB", version: "1.2" },
];

Explanation: The NonExistentComponent in the update list is ignored because it's not present in the initialComponents. The original list remains unchanged.

Example 4: Edge Case - Removal Precedes Update

// Input Components
const initialComponents = [
  { name: "ReportGenerator", version: "beta" },
  { name: "DataProcessor", version: "alpha" },
];

// Input Migration Plan
const migrationPlan = {
  update: [
    { name: "ReportGenerator", newVersion: "release" }, // This will be ignored due to removal
  ],
  remove: [
    "ReportGenerator",
  ],
};

// Expected Output Components
const expectedOutput = [
  { name: "DataProcessor", version: "alpha" },
];

Explanation: ReportGenerator is marked for removal, which takes precedence over the update. Therefore, it is removed from the final list.

Constraints

• Component names are unique strings within a given list.
• Versions are represented as strings.
• The migration plan's remove array contains only component names (strings).
• The migration plan's update array contains objects with name and newVersion properties.
• The input component list and migration plan will be valid according to the described structures.
• Performance is not a primary concern for this challenge, but an efficient solution is always appreciated.

Notes

• Consider using a Map or an object for efficient lookups when processing the migration plan against the components.
• The goal is to create a function that takes the initialComponents and migrationPlan and returns a new array of components. Do not modify the original initialComponents array.
• Think about how you would structure your types for clarity and maintainability in TypeScript.