POC

src/index.ts

@@ -1 +1,56 @@
-console.log('hello')
+export type Result<T, E> = { type: 'ok'; value: T } | { type: 'error'; value: E }
+
+export type Status = 'created' | 'pending' | 'done'
+
+export class Future<T> {
+    constructor(
+        public fn: (done: (result: T) => void) => void,
+        public thenFn?: (result: T) => void,
+        public status: Status = 'created'
+    ) {}
+
+    map(mapFn: (result: T) => void): Future<T> {
+        this.thenFn = mapFn
+        return this
+    }
+}
+
+export class Runtime {
+    private queue: Future<any>[] = []
+    private pending: Future<any>[] = []
+
+    loop(): void {
+        if (this.queue.length !== 0) {
+            const future = this.queue.splice(0, 1)[0]
+            future.status = 'pending'
+            this.pending.push(future)
+            future.fn(res => {
+                future.thenFn?.(res)
+                future.status = 'done'
+                this.pending.splice(this.pending.indexOf(future), 1)
+            })
+        }
+        if (this.queue.length !== 0 || this.pending.length !== 0) {
+            setTimeout(() => this.loop(), 10)
+        }
+    }
+
+    spawn(future: Future<any>): void {
+        this.queue.push(future)
+    }
+}
+export const runtime = new Runtime()
+
+runtime.spawn(
+    new Future<void>(done => {
+        main()
+        done()
+    })
+)
+runtime.loop()
+
+function main() {
+    console.log('Hello, World!')
+    const f = new Future(res => setTimeout(() => res(5), 1000)).map(res => console.log('res', res))
+    runtime.spawn(f)
+}