typescript/prefer-as-const Correctness
What it does
Enforce the use of as const over literal types.
Why is this bad?
There are two common ways to tell TypeScript that a literal value should be interpreted as its literal type (e.g. 2) rather than general primitive type (e.g. number);
as const: telling TypeScript to infer the literal type automatically as with the literal type: explicitly telling the literal type to TypeScript
as const is generally preferred, as it doesn't require re-typing the literal value. This rule reports when an as with an explicit literal type can be replaced with an as const.
Examples
Examples of incorrect code for this rule:
ts
let bar: 2 = 2;
let foo = { bar: "baz" as "baz" };Examples of correct code for this rule:
ts
let foo = "bar";
let foo = "bar" as const;
let foo: "bar" = "bar" as const;
let bar = "bar" as string;
let foo = { bar: "baz" };How to use
To enable this rule using the config file or in the CLI, you can use:
json
{
"rules": {
"typescript/prefer-as-const": "error"
}
}ts
import { defineConfig } from "oxlint";
export default defineConfig({
rules: {
"typescript/prefer-as-const": "error",
},
});bash
oxlint --deny typescript/prefer-as-constVersion
This rule was added in v0.0.8.