Zig Requires Chilkat v11.4.0+

Call a JavaScript Function Returning a String

See more JavaScript Examples

Demonstrates how to call a JavaScript function that returns a string. Zig

const std = @import("std");
const chilkat = @import("chilkat");

pub fn main(init: std.process.Init) !void {
    const alloc = init.arena.allocator();

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

    // function greet(name) {
    //     return "Hello, " + name + "!";
    // }

    const sb_script = try chilkat.StringBuilder.init();
    defer sb_script.deinit();
    sb_script.append("function greet(name) { return \"Hello, \" + name + \"!\"; }") catch {};

    const js = try chilkat.Js.init();
    defer js.deinit();

    const result = try chilkat.JsonObject.init();
    defer result.deinit();
    result.setEmitCompact(false);

    // Call Eval to add the function to the context's global object
    js.eval(sb_script, result) catch {
        // Examine the result for an exception.
        std.debug.print("{s}\n", .{try result.emit(alloc)});

        // Also examine the LastErrorText.
        std.debug.print("{s}\n", .{try js.getLastErrorText(alloc)});
        return;
    };

    // ------------------------------------------------------------------------------
    // Call the function greet("Michael")

    const func_call = try chilkat.JsonObject.init();
    defer func_call.deinit();

    // Create JSON specifying the function name and arguments

    // {
    //   "name": "greet",
    //   "args": [ "Michael" ]
    // }

    func_call.updateString("name", "greet") catch {};
    func_call.updateString("args[0]", "Michael") catch {};

    js.callFunction(func_call, result) catch {
        // Examine the result for an exception.
        std.debug.print("{s}\n", .{try result.emit(alloc)});

        // Also examine the LastErrorText.
        std.debug.print("{s}\n", .{try js.getLastErrorText(alloc)});
        return;
    };

    std.debug.print("{s}\n", .{try result.emit(alloc)});

    // Output:
    // {
    //   "type": "string",
    //   "value": "Hello, Michael!"
    // }

    const retval = try result.stringOf(alloc, "value");
    std.debug.print("{s}\n", .{retval});

    // Output:
    // Hello, Michael!
}