topLevelAwaits

Reports top-level await expressions in files that export values.

✅ This rule is included in the ts logicalStrict presets.

Top-level await (“TLA”) allows using await at the module level. While convenient for standalone files run like scripts, it can cause issues if those files are imported by other modules:

Modules using top-level await block their dependents until the await resolves
This can cause unexpected delays in application startup
It makes module loading order slower and sometimes less predictable

const 
const config: any
config = await import("./config.json");
export const 
const apiUrl: any
apiUrl = 
const config: any
config.
any
apiUrl;

const 
const data: any
data = await 
function fetch(input: string | URL | Request, init?: RequestInit): Promise<Response> (+1 overload)
MDN Reference
fetch("/api/data").
Promise<Response>.then<any, never>(onfulfilled?: ((value: Response) => any) | null | undefined, onrejected?: ((reason: any) => PromiseLike<never>) | null | undefined): Promise<any>
Attaches callbacks for the resolution and/or rejection of the Promise.
@param ― onfulfilled The callback to execute when the Promise is resolved.
@param ― onrejected The callback to execute when the Promise is rejected.
@returns ― A Promise for the completion of which ever callback is executed.
then((
r: Response
r) => 
r: Response
r.
Body.json(): Promise<any>
MDN Reference
json());
export { 
const data: any
export data
data };

let 
let config: Config
config: 
type Config = {
    [x: string]: unknown;
}
Config;

export async function 
function getConfig(): Promise<Config>
getConfig() {
  if (!
let config: Config
config) {
    
let config: Config
config = await import("./config.json");
  }
  return 
let config: Config
config;
}

export async function 
function fetchData(): Promise<any>
fetchData() {
  return 
function fetch(input: string | URL | Request, init?: RequestInit): Promise<Response> (+1 overload)
MDN Reference
fetch("/api/data").
Promise<Response>.then<any, never>(onfulfilled?: ((value: Response) => any) | null | undefined, onrejected?: ((reason: any) => PromiseLike<never>) | null | undefined): Promise<any>
Attaches callbacks for the resolution and/or rejection of the Promise.
@param ― onfulfilled The callback to execute when the Promise is resolved.
@param ― onrejected The callback to execute when the Promise is rejected.
@returns ― A Promise for the completion of which ever callback is executed.
then((
r: Response
r) => 
r: Response
r.
Body.json(): Promise<any>
MDN Reference
json());
}

Options

This rule is not configurable.

When Not To Use It

If you’re intentionally using top-level await for module initialization and understand the implications for module loading, you may disable this rule. You might consider using Flint disable comments and/or configuration file disables for those specific situations instead of completely disabling this rule.

Equivalents in Other Linters

ESLint: unicorn/prefer-top-level-await

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topLevelAwaits

Examples

Options

When Not To Use It

Further Reading

Equivalents in Other Linters