Theo's Typesafe Cult•8mo ago

Is it idiomatic TypeScript: using as const?

Hi, this is typescript related. Is there a way to avoid <const> or as const hell? I have an object type that has several fields that are unions for example:

type CssLayout = {
  display: "flex" | "grid" | "block";
}

type CssLayout = {
  display: "flex" | "grid" | "block";
}

then inside code:

const someData = {
  display: <const> "flex",
  ...
...
}

const someData = {
  display: <const> "flex",
  ...
...
}

Is this idiomatic TypeScript? or am I commiting a crime?

2 Replies

Rhys•8mo ago

Const isn’t even a valid operator there is it? Either put a type on someData, I.e someData: {display: “flex” | “block” } or cast display to the type, I.e { display: “flex” as Alignment } Typescript infers display as a string rather than your union type since someone could do someData.display = “foo” in between you declaring it and using it so you need to strongly type it

Boris Povolotsky•8mo ago

It is, but I figured using as Alignment makes more sense.

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Is it idiomatic TypeScript: using as const?