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Wasm

Wasm runtime

The Wasm runtime enables the execution of functions authored in any language that can be compiled into WebAssembly and that follows the component model.

Common use cases:

  • Integrating an existing WebAssembly component
  • Building language-agnostic services

Example

Here is a simple wit component description using wit IDL that exports the add function.

package example:host;
world host {
export add: func(a: u32, b: u32) -> u32;
}

In your typegraph:

import { Policy, t, typegraph } from "@typegraph/sdk";
import { WasmRuntime } from "@typegraph/sdk/runtimes/wasm.js";

typegraph("example", (g) => {
const pub = Policy.public();
const wasm = WasmRuntime.reflected("path/to/your-compiled-component.wasm");

g.expose({
add: wasm.export(
t.struct({ a: t.integer(), b: t.integer() }),
t.integer(),
{
name: "add", // exported function
},
).withPolicy(pub),
});
});

Wit to Typegraph types

Wit ensures that you have statically typed values backed directly in your component. You can refer to the correspondence table bellow in how the input/output values are shaped in your typegraph.

wittypegraphExample values
stringt.string(), t.uuid()"Hello world", "H", ..
u8, u16, u32, u64, s8, s16, s32, s64t.integer(), t.float()1, 2, 0, ..
f32, f64t.float()3.14, 100, 2, ..
chart.string() (truncated), t.integer() (truncated as u8), t.float() (truncated as u8)"A", 65, 65.0, ..
option<T><T>.optional()null, "hello world", ..
list<T>t.list(<T>)["one", "two" ], [1, 2], ..
tuple<T1, T2, ..>t.list(t.enum([t1, t2, ..]))[1, "one"], [2, "two"], ..
enum example { one, two }t.enum(["one", "two"])"one", "two"
variant example { one(string), two }t.struct({ "tag": t.enum(["one", "two"]), "value": t.string().optional() ){ "tag": "two", "value": null }
record example { id: string, description: option<string> }t.struct({ "id": t.integer(), "description": t.string().optional() ){ "id": 123, "description": "some text"}
flags example { read, write, delete }t.list(t.enum(["read", "write", "delete"]))["read"], ["read", "write", "delete"], ..