intro-to-effect

1-await-try-catch.ts

try {
  const doc = await s3.getObject();
} catch (err) {
   // error is any or unknown
   if (err instanceof ObjectNotFoundError) {
     // TODO: handle error
   }
}

2-vs-promise1.ts

// Promise<number>
const task = new Promise<number>((resolve, reject) => {
  setTimeout(() => {
    Math.random() > 0.5 ? resolve(2) : reject("Uh oh!")
  }, 300)
});

// vs

// Effect.Effect<number, string, never>
const task = Effect.gen(function* () {
  yield* Effect.sleep("300 millis")
  return Math.random() > 0.5 ? 2 : yield* Effect.fail("Uh oh!")
});

3-vs-promise2.ts

// Promise<number>
const task = async () => {
  await promisify(setTimeout)(300);
  return Math.random() > 0.5 ? resolve(2) : reject("Uh oh!");
};

// vs

// Effect.Effect<number, string, never>
const task = Effect.gen(function* () {
  yield* Effect.sleep("300 millis")
  return Math.random() > 0.5 ? 2 : yield* Effect.fail("Uh oh!")
})

4-then vs map.ts

// Promise<number>
const length = Promise.resolve("Hello")
  .then((s) => s.length);
  
//vs

// Effect.Effect<number, never, never>
const length = Effect.succeed("Hello").pipe(
  Effect.map((s) => s.length)
)

5-await vs yield.ts

async function main() {
  // number
  const length = (await Promise.resolve("Hello")).length;
}

Effect.gen(function* () {
  // number
  const length = (yield* Effect.succeed("Hello")).length;
});

7-basic-flow.ts

// Effect.Effect<number, string, never>
const randomNumber = () => Effect.gen(function* () {
  return Math.random() > 0.5 ? 2 : yield* Effect.fail("Uh oh!")
});

const program = Effect.gen(function* () {
  const randomNumber = yield* randomNumber();
  console.log(`Randon number: ${randomNumber}`);
});
 
Effect.runFork(program)