Struct quick::Context

pub struct Context { /* fields omitted */ }

Methods

impl Context

pub fn new() -> Result<Self, ContextError>

pub fn eval(&self, code: &str) -> Result<JsValue, ExecutionError>

Evaluates Javascript code and returns the value of the final expression.

use quick::{Context, JsValue};
let context = Context::new().unwrap();

let value = context.eval(" 1 + 2 + 3 ");
assert_eq!(
    value,
    Ok(JsValue::Int(6)),
);

let value = context.eval(r#"
    function f() { return 55 * 3; }
    let y = f();
    var x = y.toString() + "!"
    x
"#);
assert_eq!(
    value,
    Ok(JsValue::String("165!".to_string())),
);

pub fn eval_as<R>(&self, code: &str) -> Result<R, ExecutionError> where
    R: TryFrom<JsValue>,
    R::Error: Into<ValueError>, 

Evaluates Javascript code and returns the value of the final expression as a Rust type.

use quick::{Context};
let context = Context::new().unwrap();

let res = context.eval_as::<bool>(" 100 > 10 ");
assert_eq!(
    res,
    Ok(true),
);

let value: i32 = context.eval_as(" 10 + 10 ").unwrap();
assert_eq!(
    value,
    20,
);

pub fn call_function(
    &self,
    function_name: &str,
    args: impl IntoIterator<Item = impl Into<JsValue>>
) -> Result<JsValue, ExecutionError>

Call a global function in the Javascript namespace.

use quick::{Context, JsValue};
let context = Context::new().unwrap();

let res = context.call_function("encodeURIComponent", vec!["a=b"]);
assert_eq!(
    res,
    Ok(JsValue::String("a%3Db".to_string())),
);

pub fn add_callback<F>(
    &self,
    name: &str,
    callback: impl Callback<F> + 'static
) -> Result<(), ExecutionError>

Add a global JS function that is backed by a Rust function or closure.

use quick::{Context, JsValue};
let context = Context::new().unwrap();

// Register a closue as a callback under the "add" name.
// The 'add' function can now be called from Javascript code.
context.add_callback("add", |a: i32, b: i32| { a + b }).unwrap();

// Now we try out the 'add' function via eval.
let output = context.eval_as::<i32>(" add( 3 , 4 ) ").unwrap();
assert_eq!(
    output,
    7,
);