Struct RuntimeValue

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pub struct RuntimeValue { /* private fields */ }

Expand description

A JS value with an attached guard that keeps it alive until dropped.

This struct ensures that GC-managed objects remain valid for as long as the RuntimeValue exists. The guard is private to prevent accidental extraction of the value without the guard.

§Creating RuntimeValues

For primitives (no GC needed):

use tsrun::{RuntimeValue, JsValue};

let num = RuntimeValue::unguarded(JsValue::from(42.0));
assert_eq!(num.as_number(), Some(42.0));

let text = RuntimeValue::unguarded(JsValue::from("hello"));
assert_eq!(text.as_str(), Some("hello"));

For objects returned from execution:

use tsrun::{Interpreter, StepResult};

let mut interp = Interpreter::new();
interp.prepare("({ x: 1, y: 2 })", None).unwrap();

loop {
    match interp.step().unwrap() {
        StepResult::Continue => continue,
        StepResult::Complete(value) => {
            // value is a RuntimeValue keeping the object alive
            assert!(value.is_object());
            break;
        }
        _ => break,
    }
}

Implementations§

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impl RuntimeValue

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pub fn unguarded(value: JsValue) -> Self

Create an unguarded RuntimeValue (for primitives). Use this for values that don’t need GC protection (strings, numbers, booleans, null, undefined).

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pub fn value(&self) -> &JsValue

Get a reference to the value

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pub fn is_undefined(&self) -> bool

Check if this is undefined

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pub fn is_null(&self) -> bool

Check if this is null

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pub fn is_nullish(&self) -> bool

Check if this is null or undefined

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pub fn is_boolean(&self) -> bool

Check if this is a boolean

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pub fn is_number(&self) -> bool

Check if this is a number

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pub fn is_string(&self) -> bool

Check if this is a string

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pub fn is_object(&self) -> bool

Check if this is an object

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pub fn as_bool(&self) -> Option<bool>

Returns the boolean value if this is a Boolean, otherwise None

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pub fn as_number(&self) -> Option<f64>

Returns the numeric value if this is a Number, otherwise None

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pub fn as_str(&self) -> Option<&str>

Returns the string slice if this is a String, otherwise None

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pub fn type_name(&self) -> &'static str

Returns a string describing the type of this value

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pub fn len(&self) -> Option<usize>

Get the length of an array.

Returns None if this is not an array.

§Example

let arr = runtime.create_from_json(&json!([1, 2, 3, 4, 5]))?;
assert_eq!(arr.len(), Some(5));

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pub fn is_empty(&self) -> Option<bool>

Check if the array is empty.

Returns None if this is not an array.

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pub fn is_array(&self) -> bool

Check if this value is an array.

§Example

let arr = runtime.create_from_json(&json!([1, 2, 3]))?;
let obj = runtime.create_from_json(&json!({"x": 1}))?;
assert!(arr.is_array());
assert!(!obj.is_array());

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pub fn keys(&self) -> Vec<String>

Get all property keys of an object.

Returns an empty vector if this is not an object.

§Example

let obj = runtime.create_from_json(&json!({"a": 1, "b": 2}))?;
let keys = obj.keys();
assert!(keys.contains(&"a".to_string()));
assert!(keys.contains(&"b".to_string()));

Methods from Deref<Target = JsValue>§

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pub fn is_null_or_undefined(&self) -> bool

Check if this value is null or undefined

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pub fn is_callable(&self) -> bool

Check if this value is callable (a function)

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pub fn is_string(&self) -> bool

Check if this is a string value

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pub fn is_undefined(&self) -> bool

Check if this is undefined

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pub fn is_null(&self) -> bool

Check if this is null

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pub fn is_nullish(&self) -> bool

Check if this is null or undefined (alias for is_null_or_undefined)

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pub fn is_boolean(&self) -> bool

Check if this is a boolean

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pub fn is_number(&self) -> bool

Check if this is a number

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pub fn is_object(&self) -> bool

Check if this is an object

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pub fn is_symbol(&self) -> bool

Check if this is a symbol

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pub fn as_bool(&self) -> Option<bool>

Returns the boolean value if this is a Boolean, otherwise None

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pub fn as_number(&self) -> Option<f64>

Returns the numeric value if this is a Number, otherwise None

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pub fn as_str(&self) -> Option<&str>

Returns the string slice if this is a String, otherwise None

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pub fn as_js_string(&self) -> Option<&JsString>

Returns a reference to the JsString if this is a String, otherwise None

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pub fn as_object(&self) -> Option<&Gc<JsObject>>

Returns a reference to the object if this is an Object, otherwise None

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pub fn as_symbol(&self) -> Option<&JsSymbol>

Returns a reference to the symbol if this is a Symbol, otherwise None

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pub fn guard_by(&self, guard: &Guard<JsObject>)

If this value is an object, add it to the guard. This keeps the object alive as long as the guard exists.

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pub fn to_boolean(&self) -> bool

Convert to boolean (ToBoolean)

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pub fn to_number(&self) -> f64

Convert to number (ToNumber)

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pub fn to_js_string(&self) -> JsString

Convert to string (ToString) Note: Prefer using Interpreter::to_js_string() which uses interned strings. This method is kept for internal use in value.rs, Debug impl, and tests.

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