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typescript/no-floating-promises Correctness

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Qué hace

Esta regla prohíbe "floating" Promises in TypeScript code, which is a Promise that is created without any code to handle its resolution or rejection.

This rule will report Promise-valued statements that are not treated in one of the following ways:

• Calling its .then() with two arguments
• Calling its .catch() with one argument
• awaiting it
• returning it
• voiding it

This rule also reports when an Array containing Promises is created and not properly handled. The main way to resolve this is by using one of the Promise concurrency methods to create a single Promise, then handling that according to the procedure above. These methods include:

• Promise.all()
• Promise.allSettled()
• Promise.any()
• Promise.race()

¿Por qué es problemático?

Floating Promises can cause several issues, such as improperly sequenced operations, ignored Promise rejections, and more.

Ejemplos

Ejemplos de código incorrecto para esta regla:

const promise = new Promise((resolve, reject) => resolve("value"));
promise;

async function returnsPromise() {
  return "value";
}
returnsPromise().then(() => {});

Promise.reject("value").catch();

Promise.reject("value").finally();

[1, 2, 3].map(async (x) => x + 1);

Ejemplos de código correcto para esta regla:

const promise = new Promise((resolve, reject) => resolve("value"));
await promise;

async function returnsPromise() {
  return "value";
}

void returnsPromise();

returnsPromise().then(
  () => {},
  () => {},
);

Promise.reject("value").catch(() => {});

await Promise.reject("value").finally(() => {});

await Promise.all([1, 2, 3].map(async (x) => x + 1));

Configuración

Esta regla acepta un objeto de configuración con las siguientes propiedades:

allowForKnownSafeCalls

tipo: array

predeterminado: []

Allows specific calls to be ignored, specified as type or value specifiers.

allowForKnownSafeCalls[n]

tipo: object | string

Type or value specifier for matching specific declarations

Supports four types of specifiers:

1. String specifier (deprecated): Universal match by name

"Promise"

2. File specifier: Match types/values declared in local files

{ "from": "file", "name": "MyType" }
{ "from": "file", "name": ["Type1", "Type2"] }
{ "from": "file", "name": "MyType", "path": "./types.ts" }

3. Lib specifier: Match TypeScript built-in lib types

{ "from": "lib", "name": "Promise" }
{ "from": "lib", "name": ["Promise", "PromiseLike"] }

4. Package specifier: Match types/values from npm packages

{ "from": "package", "name": "Observable", "package": "rxjs" }
{ "from": "package", "name": ["Observable", "Subject"], "package": "rxjs" }

allowForKnownSafeCalls[n].from

tipo: "file"

allowForKnownSafeCalls[n].name

tipo: array | string

Name specifier that can be a single string or array of strings

allowForKnownSafeCalls[n].name[n]

tipo: string

allowForKnownSafeCalls[n].path

tipo: string

Optional file path to specify where the types or values must be declared. If omitted, all files will be matched.

allowForKnownSafePromises

tipo: array

predeterminado: []

Allows specific Promise types to be ignored, specified as type or value specifiers.

allowForKnownSafePromises[n]

tipo: object | string

Type or value specifier for matching specific declarations

Supports four types of specifiers:

1. String specifier (deprecated): Universal match by name

"Promise"

2. File specifier: Match types/values declared in local files

{ "from": "file", "name": "MyType" }
{ "from": "file", "name": ["Type1", "Type2"] }
{ "from": "file", "name": "MyType", "path": "./types.ts" }

3. Lib specifier: Match TypeScript built-in lib types

{ "from": "lib", "name": "Promise" }
{ "from": "lib", "name": ["Promise", "PromiseLike"] }

4. Package specifier: Match types/values from npm packages

{ "from": "package", "name": "Observable", "package": "rxjs" }
{ "from": "package", "name": ["Observable", "Subject"], "package": "rxjs" }

allowForKnownSafePromises[n].from

tipo: "file"

allowForKnownSafePromises[n].name

tipo: array | string

Name specifier that can be a single string or array of strings

allowForKnownSafePromises[n].name[n]

tipo: string

allowForKnownSafePromises[n].path

tipo: string

Optional file path to specify where the types or values must be declared. If omitted, all files will be matched.

checkThenables

tipo: boolean

predeterminado: false

Check for thenable objects that are not necessarily Promises.

ignoreIIFE

tipo: boolean

predeterminado: false

Ignore immediately invoked function expressions (IIFEs).

ignoreVoid

tipo: boolean

predeterminado: true

Ignore Promises that are void expressions.

Cómo usarla

To enable this rule using the config file or in the CLI, you can use:

Config (.oxlintrc.json)

{
  "options": {
    "typeAware": true
  },
  "rules": {
    "typescript/no-floating-promises": "error"
  }
}

Config (oxlint.config.ts)

import { defineConfig } from "oxlint";

export default defineConfig({
  options: { typeAware: true },
  rules: {
    "typescript/no-floating-promises": "error",
  },
});

CLI

oxlint --type-aware --deny typescript/no-floating-promises

Versión

Esta regla se añadió en v1.11.0.

Referencias

• Rule Source
• Rule Source (tsgolint)