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useFlatMap (since v1.0.0)

Diagnostic Category: lint/complexity/useFlatMap

Sources:

Promotes the use of .flatMap() when map().flat() are used together.

Examples

Section titled Examples

Invalid

Section titled Invalid
const array = ["split", "the text", "into words"];
array.map(sentence => sentence.split(' ')).flat();
code-block.js:2:1 lint/complexity/useFlatMap  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ✖ The call chain .map().flat() can be replaced with a single .flatMap() call.
  
    1 │ const array = ["split", "the text", "into words"];
  > 2 │ array.map(sentence => sentence.split(' ')).flat();
      │ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    3 │ 
  
  ℹ Safe fix: Replace the chain with .flatMap().
  
    1 1 │   const array = ["split", "the text", "into words"];
    2   │ - array.map(sentence·=>·sentence.split('·')).flat();
      2 │ + array.flatMap(sentence·=>·sentence.split('·'));
    3 3 │   
  

const array = ["split", "the text", "into words"];
array.map(sentence => sentence.split(' ')).flat(1);
code-block.js:2:1 lint/complexity/useFlatMap  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ✖ The call chain .map().flat() can be replaced with a single .flatMap() call.
  
    1 │ const array = ["split", "the text", "into words"];
  > 2 │ array.map(sentence => sentence.split(' ')).flat(1);
      │ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    3 │ 
  
  ℹ Safe fix: Replace the chain with .flatMap().
  
    1 1 │   const array = ["split", "the text", "into words"];
    2   │ - array.map(sentence·=>·sentence.split('·')).flat(1);
      2 │ + array.flatMap(sentence·=>·sentence.split('·'));
    3 3 │

Valid

Section titled Valid
const array = ["split", "the text", "into words"];
array.map(sentence => sentence.split(' ')).flat(2);
Section titled Related links