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noThenProperty (since v1.5.0)

Diagnostic Category: lint/suspicious/noThenProperty

Sources:

Disallow then property.

When combining objects with a then method (thenable objects) with await expressions or dynamic imports, caution is necessary. These syntaxes interpret the object’s then method as intended for the resolution or rejection of a promise, which can lead to unexpected behavior or errors.

Examples

Section titled Examples

Invalid

Section titled Invalid
export {then};
suspicious/noThenProperty.js:1:9 lint/suspicious/noThenProperty ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ✖ Do not export then.
  
  > 1 │ export {then};
      │         ^^^^
    2 │ 
  

const foo = {
    then() {}
};
suspicious/noThenProperty.js:2:5 lint/suspicious/noThenProperty ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ✖ Do not add then to an object.
  
    1 │ const foo = {
  > 2 │     then() {}
      │     ^^^^
    3 │ };
    4 │ 
  

const foo = {
    get then() {}
};
suspicious/noThenProperty.js:2:9 lint/suspicious/noThenProperty ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ✖ Do not add then to an object.
  
    1 │ const foo = {
  > 2 │     get then() {}
      │         ^^^^
    3 │ };
    4 │ 
  

const foo = {
   get then() {}
};
suspicious/noThenProperty.js:2:8 lint/suspicious/noThenProperty ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ✖ Do not add then to an object.
  
    1 │ const foo = {
  > 2 │    get then() {}
      │        ^^^^
    3 │ };
    4 │ 
  

foo.then = function () {}
suspicious/noThenProperty.js:1:1 lint/suspicious/noThenProperty ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ✖ Do not add then to an object.
  
  > 1 │ foo.then = function () {}
      │ ^^^^^^^^
    2 │ 
  

class Foo {
    then() {}
}
suspicious/noThenProperty.js:2:5 lint/suspicious/noThenProperty ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ✖ Do not add then to a class.
  
    1 │ class Foo {
  > 2 │     then() {}
      │     ^^^^
    3 │ }
    4 │ 
  

class Foo {
    static then() {}
}
suspicious/noThenProperty.js:2:12 lint/suspicious/noThenProperty ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ✖ Do not add then to a class.
  
    1 │ class Foo {
  > 2 │     static then() {}
      │            ^^^^
    3 │ }
    4 │

Valid

Section titled Valid
export {then as success};
const foo = {
    success() {}
};
class Foo {
    success() {}
}
const foo = bar.then;
Section titled Related links