Rust Requires Chilkat v11.4.0+

Call a JavaScript Function Returning an Object

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Demonstrates how to call a JavaScript function that returns an object. Rust

// This is the JavaScript function we'll call:

// function getSettings() {
//     return {
//         theme: "dark",
//         notifications: true,
//         version: 1.0
//     };
// }

let sb_script = chilkat::StringBuilder::new();
let _ = sb_script.append("function getSettings() {");
let _ = sb_script.append("    return {");
let _ = sb_script.append("        theme: \"dark\",");
let _ = sb_script.append("        notifications: true,");
let _ = sb_script.append("        version: 1.0");
let _ = sb_script.append("    };");
let _ = sb_script.append("}");

let js = chilkat::Js::new();

let result = chilkat::JsonObject::new();
result.set_emit_compact(false);

// Call Eval to add the function to the context's global object
if js.eval(&sb_script, &result).is_err() {
    // Examine the result for an exception.
    println!("{}", result.emit().unwrap_or_default());

    // Also examine the LastErrorText.
    println!("{}", js.last_error_text());
    return;
}

// ------------------------------------------------------------------------------
// Call the function getSettings()

let func_call = chilkat::JsonObject::new();

// Create JSON specifying the function name and arguments
// The function has no arguments, so we only specify the name.

// {
//   "name": "getSettings",
// }

let _ = func_call.update_string("name", "getSettings");

if js.call_function(&func_call, &result).is_err() {
    // Examine the result for an exception.
    println!("{}", result.emit().unwrap_or_default());

    // Also examine the LastErrorText.
    println!("{}", js.last_error_text());
    return;
}

println!("{}", result.emit().unwrap_or_default());

// Output:
// {
//   "type": "object",
//   "value": {
//     "theme": "dark",
//     "notifications": true,
//     "version": 1
//   }
// }

// Examine the object's members
println!("theme: {}", result.string_of("value.theme").unwrap_or_default());
println!("notifications: {}", result.bool_of("value.notifications"));
println!("version: {}", result.int_of("value.version"));

// Output:
// theme: dark
// notifications: True
// version: 1