complete/strict-array-methods

💼 This rule is enabled in the ✅ recommended config.

📝 Requires boolean return types on some specific array methods.

💭 This rule requires type information.

Rule Details

This rule targets the following Array methods:

• Array.prototype.every
• Array.prototype.filter
• Array.prototype.find
• Array.prototype.findIndex
• Array.prototype.findLast
• Array.prototype.findLastIndex
• Array.prototype.some

Normally, the @typescript-eslint/strict-boolean-expressions ESLint rule catches bugs where you are supposed to put a boolean value but accidentally put something else. Unfortunately, that rule does not catch this mistake when using array methods.

Thus, an additional ESLint rule is necessary to handle this.

// Bad
const numbers: number[] = [];
const filteredNumbers = numbers.filter((element) => {
  return element;
});

// Good
const numbers: number[] = [];
const filteredNumbers = numbers.filter((element) => {
  return element !== 0;
});

Options

This rule is not configurable.

Resources

• How to use this rule
• Rule source
• Test source