Struct deno_core::JsRealm

pub struct JsRealm(_);

A representation of a JavaScript realm tied to a JsRuntime, that allows execution in the realm’s context.

A JsRealm instance is a reference to an already existing realm, which does not hold ownership of it, so instances can be created and dropped as needed. As such, calling JsRealm::new doesn’t create a new realm, and cloning a JsRealm only creates a new reference. See JsRuntime::create_realm to create new realms instead.

Despite JsRealm instances being references, multiple instances that point to the same realm won’t overlap because every operation requires passing a mutable reference to the v8::Isolate. Therefore, no operation on two JsRealm instances tied to the same isolate can be run at the same time, regardless of whether they point to the same realm.

Panics

Every method of JsRealm will panic if you call it with a reference to a v8::Isolate other than the one that corresponds to the current context.

In other words, the v8::Isolate parameter for all the related JsRealm methods must be extracted from the pre-existing JsRuntime.

Example usage with the JsRealm::execute_script method:

use deno_core::JsRuntime;
use deno_core::RuntimeOptions;

let mut runtime = JsRuntime::new(RuntimeOptions::default());
let new_realm = runtime
        .create_realm()
        .expect("Handle the error properly");
let source_code = "var a = 0; a + 1";
let result = new_realm
        .execute_script_static(runtime.v8_isolate(), "<anon>", source_code)
        .expect("Handle the error properly");

Lifetime of the realm

As long as the corresponding isolate is alive, a JsRealm instance will keep the underlying V8 context alive even if it would have otherwise been garbage collected.

Implementations

impl JsRealm

pub fn new(context: Global<Context>) -> Self

pub fn context(&self) -> &Global<Context>

pub fn handle_scope<'s>(&self, isolate: &'s mut Isolate) -> HandleScope<'s>

For info on the v8::Isolate parameter, check JsRealm.

pub fn global_object<'s>(&self, isolate: &'s mut Isolate) -> Local<'s, Object>

For info on the v8::Isolate parameter, check JsRealm.

pub fn execute_script_static( &self, isolate: &mut Isolate, name: &'static str, source_code: &'static str ) -> Result<Global<Value>, Error>

Executes traditional JavaScript code (traditional = not ES modules) in the realm’s context.

For info on the v8::Isolate parameter, check JsRealm.

The name parameter can be a filepath or any other string. E.g.:

• “/some/file/path.js”
• “”
• “[native code]”

The same name value can be used for multiple executions.

Error can usually be downcast to JsError.

pub fn execute_script( &self, isolate: &mut Isolate, name: &'static str, source_code: ModuleCode ) -> Result<Global<Value>, Error>

Executes traditional JavaScript code (traditional = not ES modules) in the realm’s context.

For info on the v8::Isolate parameter, check JsRealm.

The name parameter can be a filepath or any other string. E.g.:

• “/some/file/path.js”
• “”
• “[native code]”

The same name value can be used for multiple executions.

Error can usually be downcast to JsError.

Trait Implementations

impl Clone for JsRealm

fn clone(&self) -> JsRealm

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.