Struct IndexSignatureResolver 

pub struct IndexSignatureResolver<'a> { /* private fields */ }

Resolver for index signature queries on types.

This struct provides a unified interface for querying index signatures across different type representations (ObjectWithIndex, Union, etc.).

Implementations

impl<'a> IndexSignatureResolver<'a>

pub fn new(db: &'a dyn TypeDatabase) -> Self

Create a new index signature resolver.

pub fn resolve_string_index(&self, obj: TypeId) -> Option<TypeId>

Resolve the string index signature type from an object type.

Returns Some(value_type) if the object has a string index signature, None otherwise.

Examples

• { [key: string]: number } → Some(TypeId::NUMBER)
• { [key: string]: string } → Some(TypeId::STRING)
• { a: number } → None

pub fn resolve_number_index(&self, obj: TypeId) -> Option<TypeId>

Resolve the numeric index signature type from an object type.

Returns Some(value_type) if the object has a numeric index signature, None otherwise.

Examples

• { [key: number]: string } → Some(TypeId::STRING)
• { [key: number]: number } → Some(TypeId::NUMBER)
• { a: number } → None

Note: Array and tuple types have implicit numeric index signatures.

pub fn is_readonly(&self, obj: TypeId, kind: IndexKind) -> bool

Check if an index signature is readonly.

Parameters

• obj: The type to check
• kind: Which index signature to check (string or number)

Returns

true if the requested index signature is readonly, false otherwise.

Examples

• { readonly [x: string]: string } with IndexKind::String → true
• { [x: string]: string } with IndexKind::String → false

pub fn get_index_info(&self, obj: TypeId) -> IndexInfo

Get all index signatures from a type.

Returns an IndexInfo struct containing both string and numeric index signatures if present.

pub fn has_index_signature(&self, obj: TypeId, kind: IndexKind) -> bool

Check if a type has a specific index signature.

Parameters

• obj: The type to check
• kind: Which index signature to check for (string or number)

Returns

true if the type has the requested index signature, false otherwise.

pub fn is_numeric_index_name(&self, name: &str) -> bool

Check if a property name is a valid numeric index.

Examples

• "0" → true
• "42" → true
• "foo" → false
• "-1" → false
• "NaN" → true
• "Infinity" → true