こんにちわ。nap5です。

タイトルの実装例になります。

```ts
import { Ok, Result } from "neverthrow";
import { match, P } from "ts-pattern";

type Plan = "basic" | "business" | "enterprise";
type Operation = "view" | "train" | "model" | "predict";
type Input = {
  type: Plan;
  content: {
    operations: Operation[];
  };
};

(() => {
  // https://dev.to/gvergnaud/bringing-pattern-matching-to-typescript-introducing-ts-pattern-v3-0-o1k
  const decidePlan = (input: Input): Result<string, unknown> => {
    return match(input)
      .with(
        {
          type: "basic",
          content: {
            operations: P.select("operations"),
          },
        },
        ({ operations }, v) => new Ok(`[${v.type}] ${operations.join(",")}`)
      )
      .with(
        {
          type: "business",
          content: {
            operations: P.select("operations"),
          },
        },
        ({ operations }, v) => new Ok(`[${v.type}] ${operations.join(",")}`)
      )
      .with(
        {
          type: "enterprise",
          content: {
            operations: P.select("operations"),
          },
        },
        ({ operations }, v) => new Ok(`[${v.type}] ${operations.join(",")}`)
      )
      .exhaustive();
  };
  decidePlan({
    type: "basic",
    content: { operations: ["model", "train", "predict", "view"] },
  }).match(
    (data) => {
      console.log(data);
    },
    (error) => {
      console.log(error);
    }
  );
})();

```

簡単ですが、以上です。

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