TypeScript Deprecation Type Utility

Libraries and APIs evolve over time, and sometimes functions, classes, or properties need to be replaced or removed. TypeScript provides a way to signal these changes using the @deprecated JSDoc tag. This challenge focuses on creating a TypeScript utility that leverages this JSDoc tag to generate typed warnings for deprecated code usage.

Problem Description

Your task is to create a TypeScript utility type and a corresponding function that helps in marking and warning about the deprecation of code elements. You should be able to define a deprecated function or value, and when it's used in your code, TypeScript should ideally warn you. This is crucial for maintaining codebases, guiding developers towards newer, supported APIs, and preventing the use of outdated or potentially buggy features.

Key Requirements:

1. Deprecation Signal: Create a mechanism to explicitly mark functions or values as deprecated.
2. Type-Level Warning: Develop a way for TypeScript's type system to infer and report a deprecation warning when a deprecated element is used.
3. Runtime Behavior (Optional but Recommended): If possible, implement a way to optionally trigger a runtime console.warn when a deprecated function is called.
4. Flexibility: The solution should be flexible enough to handle various types of deprecated elements (functions, values, etc.).

Expected Behavior:

When a deprecated function is called or a deprecated value is accessed, the TypeScript compiler should issue a warning. For example, if you have a deprecatedFunction and you call it like deprecatedFunction(), TypeScript should flag this. Optionally, a runtime warning should also appear in the console.

Edge Cases:

• Deprecating functions with different argument and return types.
• Deprecating properties within an object.
• Handling deprecation messages that include suggestions for alternative APIs.

Examples

Example 1: Deprecating a Function

Consider a scenario where an older greet function is being replaced by greetNew.

// This is what we want to achieve conceptually

// Define a deprecated function
function greet(name: string): string {
    return `Hello, ${name}!`;
}

// Mark it as deprecated (using some hypothetical utility)
const deprecatedGreet = deprecate(greet, { message: "Use greetNew instead.", until: "v2.0" });

// Usage that should trigger a warning
const message = deprecatedGreet("Alice"); // TypeScript should warn here
console.log(message);

// Newer function
function greetNew(name: string): string {
    return `Greetings, ${name}!`;
}

Expected TypeScript Compiler Output:

[ts]
'deprecatedGreet' is deprecated. Use greetNew instead. (until v2.0)

Expected Runtime Output:

Hello, Alice!
(And a console warning: 'deprecatedGreet' is deprecated. Use greetNew instead. (until v2.0))

Example 2: Deprecating a Value

Deprecating a constant or an enum member.

// Define a constant value
const oldApiKey = "super_secret_old_key";

// Mark it as deprecated
const deprecatedOldApiKey = deprecateValue(oldApiKey, "This API key is no longer supported.");

// Usage that should trigger a warning
const apiKey = deprecatedOldApiKey; // TypeScript should warn here
console.log(apiKey);

Expected TypeScript Compiler Output:

[ts]
'deprecatedOldApiKey' is deprecated. This API key is no longer supported.

Expected Runtime Output:

super_secret_old_key
(And a console warning: 'deprecatedOldApiKey' is deprecated. This API key is no longer supported.)

Example 3: Deprecating a Property within an Object

Deprecating a specific property of an interface or class.

interface User {
    id: number;
    name: string;
    email: string; // This property will be deprecated
}

// Assume we have a way to create a typed object with deprecations
const user: Deprecated<User, "email"> = {
    id: 1,
    name: "Bob",
    email: "bob@example.com" // Accessing this should trigger a warning
};

console.log(user.name);
console.log(user.email); // TypeScript should warn here

Expected TypeScript Compiler Output:

[ts]
Property 'email' is deprecated and will be removed in a future release.

Expected Runtime Output:

Bob
bob@example.com
(And a console warning: Accessing property 'email' is deprecated.)

Constraints

• The solution must be implemented in TypeScript.
• The core deprecation mechanism should leverage TypeScript's type system to provide compile-time warnings.
• The runtime warning should be an optional feature, ideally configurable.
• The solution should not require significant modifications to existing codebases that don't use your deprecation utility.
• The performance impact of the runtime warning should be minimal.

Notes

• Consider using JSDoc @deprecated tags as inspiration, but your solution should aim for programmatic control and type safety.
• Think about how to create generic utility types and functions that can work with various input types.
• The runtime warning could be implemented using a wrapper function.
• For type-level warnings, you might explore mapped types, conditional types, and possibly techniques that leverage the compiler's understanding of JSDoc tags (though this can be complex).
• The primary goal is to make the usage of deprecated items visible at compile time.