Struct TSTypePredicate 

#[repr(C)]
pub struct TSTypePredicate<'a> {
    pub span: Span,
    pub parameter_name: TSTypePredicateName<'a>,
    pub type_annotation: Option<Box<'a, TSTypeAnnotation<'a>>>,
    pub asserts: bool,
}

TypeScript Type Predicate

Examples

function isString(x: unknown): x is string {
//              parameter_name ^    ^^^^^^ type_annotation
    return typeof x === 'string';
}

function assertString(x: unknown): asserts x is string {
//                                 ^^^^^^^ asserts: true
    if (typeof x !== 'string') throw new TypeError('x is not a string');
}

References

• TypeScript Handbook - Type Predicates
• TypeScript Handbook - Assertion Functions

Fields

span: Span

parameter_name: TSTypePredicateName<'a>

The identifier the predicate operates on

type_annotation: Option<Box<'a, TSTypeAnnotation<'a>>>

asserts: bool

Does this predicate include an asserts modifier?

Example

declare function isString(x: any): asserts x is string; // true

Trait Implementations

impl<'new_alloc> CloneIn<'new_alloc> for TSTypePredicate<'_>

type Cloned = TSTypePredicate<'new_alloc>

The type of the cloned object.

fn clone_in( &self, allocator: &'new_alloc Allocator, ) -> <TSTypePredicate<'_> as CloneIn<'new_alloc>>::Cloned

Clone self into the given allocator. allocator may be the same one that self is already in.

fn clone_in_with_semantic_ids( &self, allocator: &'new_alloc Allocator, ) -> <TSTypePredicate<'_> as CloneIn<'new_alloc>>::Cloned

Almost identical as clone_in, but for some special type, it will also clone the semantic ids. Please use this method only if you make sure semantic info is synced with the ast node.

impl ContentEq for TSTypePredicate<'_>

fn content_eq(&self, other: &TSTypePredicate<'_>) -> bool

This method tests for contents of self and other to be equal.

fn content_ne(&self, other: &Self) -> bool

This method tests for contents of self and other not to be equal. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<'a> Debug for TSTypePredicate<'a>

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl<'a> Dummy<'a> for TSTypePredicate<'a>

fn dummy(allocator: &'a Allocator) -> TSTypePredicate<'a>

Create a dummy TSTypePredicate.

Does not allocate any data into arena.

impl ESTree for TSTypePredicate<'_>

fn serialize<S>(&self, serializer: S)

where S: Serializer,

impl Gen for TSTypePredicate<'_>

fn gen(&self, p: &mut Codegen<'_>, ctx: Context)

Generate code for an AST node.

fn print(&self, p: &mut Codegen<'_>, ctx: Context)

Generate code for an AST node. Alias for gen.

impl GetSpan for TSTypePredicate<'_>

fn span(&self) -> Span

Get the Span for an AST node.

impl GetSpanMut for TSTypePredicate<'_>

fn span_mut(&mut self) -> &mut Span

Get a mutable reference to an AST node’s Span.

impl<'a> TakeIn<'a> for TSTypePredicate<'a>

fn take_in<A>(&mut self, allocator_accessor: A) -> Self

where A: AllocatorAccessor<'a>,

Replace node with a dummy.

fn take_in_box<A>(&mut self, allocator_accessor: A) -> Box<'a, Self>

where A: AllocatorAccessor<'a>,

Replace node with a boxed dummy.