# @typescript-eslint/class-literal-property-style

> Require constants on a class to be all `readonly` fields or all getters

A class can expose a constant as a `readonly` field or as a getter that returns a literal. From the outside, you read both the same way. This rule picks one, so every class writes it the same way. By default it's the `readonly` field, which is shorter.

Only literals count: strings, numbers, booleans, `null`, regular expressions, and templates without `${}`.

{/* Generated by src/codegen/lint-rule-docs.ts. Do not edit this section. */}

## Configure

Off by default. To turn it on:

```toml bunfig.toml
[lint.rules]
"@typescript-eslint/class-literal-property-style" = "error" # or "warn"
```

Every option, set to its default:

```toml bunfig.toml
[lint.rules]
# "fields" or "getters"
"@typescript-eslint/class-literal-property-style" = ["error", "fields"]
```

{/* End of the generated section. */}

## Examples

Reported:

{/* bad */}
```ts
class Server {
  get host() {
    return "localhost";
  }
}
```

Not reported:

{/* good */}
```ts
class Server {
  readonly host = "localhost";

  // Not a literal.
  get url() {
    return `http://${this.host}`;
  }
}
```

A getter that has a setter with the same name can't become a `readonly` field, so the rule leaves it alone:

{/* good */}
```ts
class Server {
  get host() {
    return "localhost";
  }
  set host(value: string) {
    console.warn("host is fixed", value);
  }
}
```

## Options

| Option | What it does |
| --- | --- |
| `"fields"` (default) | Report a getter that only returns a literal. |
| `"getters"` | Report a `readonly` field with a literal as its value. |

{/* bad {"options": ["getters"]} */}
```ts
class Server {
  readonly host = "localhost";
}
```

{/* good {"options": ["getters"]} */}
```ts
class Server {
  get host() {
    return "localhost";
  }
}
```

With `"getters"`, a field that the constructor assigns to isn't reported:

{/* good {"options": ["getters"]} */}
```ts
class Server {
  readonly host = "localhost";

  constructor(host?: string) {
    if (host) this.host = host;
  }
}
```