Returns CatT<M, Record<string, never>>

A new CatT.

Examples

import { monad as optionMonad, none, some } from "./option.ts";
import { assertEquals } from "../deps.ts";
import { doT } from "./cat.ts";

const optionA = some(1);
const optionB = some(2);
const optionC = some(3);

const computation = doT(optionMonad)
    .addM("a", optionA)
    .addM("b", optionB)
    .addWith("bSquared", ({ b }) => b * b)
    .addM("c", optionC);

assertEquals(
    computation
        .addMWith("cSqrt", ({ c }) => {
            const sqrt = Math.sqrt(c);
            return Number.isInteger(sqrt) ? some(sqrt) : none();
        })
        .finish(({ bSquared, cSqrt }) => bSquared + cSqrt),
    none(),
);

const result = computation.finish(({ a, b, c }) => a + b + c);
assertEquals(result, some(6));
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