If a file exports one thing, that thing is what the file is for, and a default export says so. Anyone who imports it doesn't have to look up the name.
The rule skips a file if it has a default export, an export *, or an exported type or interface.
Configure
Off by default. To turn it on:
bunfig.toml
[lint.rules]
"import/prefer-default-export" = "error" # or "warn"
Every option, set to its default:
bunfig.toml
[lint.rules]
"import/prefer-default-export" = ["error", {
target = "single", # "single" or "any"
}]
Examples
Reported:
export function formatDate(date) {
return date.toISOString();
}
Not reported:
export default function formatDate(date) {
return date.toISOString();
}
export function formatDate(date) {}
export function formatTime(date) {}
export type UserId = number;
Options
| Option | Default | What it does |
|---|---|---|
target | "single" | "single" reports a file with exactly one named export. "any" reports every file that has named exports and no default export. |
With "any", this is reported:
export function formatDate(date) {}
export function formatTime(date) {}
When not to use it
Named exports keep the same name everywhere, which helps auto-import and renaming. If your project prefers them, use import/no-default-export and leave this rule off.