Angular Template Type Checking Challenge

Angular's template type checking feature helps catch errors at compile time by verifying that the expressions used in your templates are type-safe. This challenge asks you to implement a simplified version of this feature, focusing on checking the type of a single expression within a template string against a provided type. This is a crucial step in building robust and maintainable Angular applications, preventing runtime errors caused by incorrect data binding.

Problem Description

You are tasked with creating a function checkTemplateExpressionType that validates whether a given expression in an Angular template string matches a specified TypeScript type. The function should analyze the expression and determine if it aligns with the provided type. The type will be represented as a string (e.g., "string", "number", "boolean", "MyCustomType").

What needs to be achieved:

• Implement a function that takes a template expression string and a TypeScript type string as input.
• The function should return true if the expression's type is compatible with the specified TypeScript type, and false otherwise.
• The function should handle basic TypeScript types: "string", "number", "boolean", "any". It should also be able to handle a custom type represented as a string (e.g., "MyCustomType").

Key Requirements:

• The function must perform a basic type check based on the string representations of the types. No complex type inference is required.
• The function should be case-insensitive when comparing type names.
• The function should not attempt to evaluate the expression; it should only check its declared type.

Expected Behavior:

• If the expression is a literal value (e.g., "123", "true", "'hello'"), the function should infer the type based on the literal's value.
• If the expression is a variable name (e.g., "myVariable"), the function should assume the type is "any" (as we are not performing full type inference).
• If the expression is a function call (e.g., "myFunction()"), the function should assume the type is "any".
• If the expression is a complex expression (e.g., "myVariable + 1"), the function should assume the type is "any".

Edge Cases to Consider:

• Empty template expression string.
• Null or undefined input values.
• Invalid TypeScript type strings.
• Expressions containing operators or function calls.

Examples

Example 1:

Input: expression = "123", type = "number"
Output: true
Explanation: The expression "123" is a number literal, so it matches the "number" type.

Example 2:

Input: expression = "'hello'", type = "string"
Output: true
Explanation: The expression "'hello'" is a string literal, so it matches the "string" type.

Example 3:

Input: expression = "true", type = "boolean"
Output: true
Explanation: The expression "true" is a boolean literal, so it matches the "boolean" type.

Example 4:

Input: expression = "myVariable", type = "string"
Output: false
Explanation: The expression "myVariable" is a variable name. We assume it's "any" and it doesn't match "string".

Example 5:

Input: expression = "myFunction()", type = "number"
Output: false
Explanation: The expression "myFunction()" is a function call. We assume it's "any" and it doesn't match "number".

Example 6:

Input: expression = "myVariable + 1", type = "number"
Output: false
Explanation: The expression "myVariable + 1" is a complex expression. We assume it's "any" and it doesn't match "number".

Example 7:

Input: expression = "MyCustomType", type = "MyCustomType"
Output: true
Explanation: The expression is a custom type name, which matches the specified type.

Constraints

• The expression string will be no longer than 256 characters.
• The type string will be no longer than 64 characters.
• The function must return a boolean value.
• The function should handle invalid input gracefully (e.g., return false for null or undefined inputs).
• Performance is not a primary concern for this simplified implementation.

Notes

• This challenge focuses on a simplified type checking scenario. A real-world Angular template type checker would involve significantly more complex analysis and type inference.
• You can assume that the input expression will be a valid string.
• Consider using regular expressions or string manipulation techniques to extract the type from the expression.
• Remember to handle case-insensitive comparisons for type names.
• The "any" type should be considered a fallback when the expression cannot be definitively typed.