combining branches

Interesting library. I’ve been using this library: https://paarthenon.github.io/variant/ So my feedback comes from my experience with using that. One of its nice features is that you can combine branches: https://paarthenon.github.io/variant/docs/use/matching#-matcher

For example:

type FooBarBaz = {type: "foo"} | {type: "baz"} | {type: "bar"}
declare const foobarbaz: FooBarBaz;

swtich (foobarbaz.type) {
  case "foo":
  case "bar":
    // handle both foo and bar in a single branch
  case "baz: 
    // handle baz in its own branch 
}

// variant:

matcher(foobarbaz)
  .when(["foo", "bar"], (foobar) => {})
  .when({baz: (baz) => {} })
  .complete()

[gvergnaud]

I just publish the 2.2.1-next.2 pre-release which uses function overloads instead of middle rest arguments so it should work fine with all versions of TS now. The downside is that you can only pass up to 5 patterns to .with()

[gvergnaud]

I opened a PR implementing a way to give several patterns to .with() https://github.com/gvergnaud/ts-pattern/pull/18 . In the end I decided against having a oneOf helper because it complexifies the inference of the pattern type.

I published a pre-release (2.2.1-next.1), but it will only work for TS >= v4.2. I might make it TS v4 compatible before merging by using function overloads instead of using middle rest function arguments.

Feel free to try it and to give me your feedback