Interop

Phasis runs in the same PHP process as your application, so values cross between PHP and JavaScript without JSON, pipes or a second runtime. They cross by conversion: scalars map to JS primitives, PHP arrays are copied into new JS arrays and objects, and JS results are copied back into PHP arrays. A change JS makes to a converted array is not visible in the PHP array. PHP callables are the exception that stays live: they become JS functions that call straight into PHP.

This section covers the rules.

Pages

• Values — the conversion tables in both directions: numbers, strings, booleans, null/undefined, arrays, objects, and the values that do not convert.
• Host functions — bind PHP callable as JS function via $engine->setGlobal(). Argument conversion, return values, and how exceptions behave.
• Shared objects — what happens when you pass a PHP object to JS today (it arrives as undefined), and how to expose PHP state and behaviour with arrays and closures instead.
• Fetch transport — swap the default ext-curl HTTP backend for Guzzle, Symfony HttpClient, a mock, or a deny-all. Plus the policy hook for allowlisting, header injection, and per-tenant binding.
• Cookie jar — mount a get(url)/set(url, header) jar to persist cookies across fetches. In-memory, Symfony BrowserKit, or a JS-side Map.
• AbortController patterns — timeout, race, propagation, AbortSignal.any / .timeout, and how a custom PHP transport polls the signal mid-transfer.

Quick example

$engine = new Phasis\Engine();

// 1. Bind a PHP callable as a JS function
$engine->setGlobal('greet', fn (string $name) => "Hello, $name!");
echo $engine->eval('greet("world")');  // → Hello, world!

// 2. Let JS change PHP state through a closure
$total = 0;
$engine->setGlobal('add', function (int $n) use (&$total): void { $total += $n; });
$engine->eval('add(2); add(3)');
echo $total;  // → 5

// 3. Call a JS function from PHP
$engine->eval('function add(a, b) { return a + b; }');
echo $engine->call('add', 2, 3);  // → 5

See also

• API reference — the full Phasis\Engine surface.
• Web APIs — Web Platform Pack and Fetch Pack live on top of the same interop layer.