PreferFunctionalArrayMethods [rule] v0.1.0

When iterating an array to produce a derived value — a new array, a single accumulator, the first match, a boolean — use the corresponding higher-order method. The named method tells the reader what the loop is for in one word; a for loop with a hand-rolled accumulator buries that intent under index plumbing.

Checks

• Mapping uses array.map(fn), not a for loop pushing into a fresh array.
• Filtering uses array.filter(predicate).
• Aggregating to a scalar uses array.reduce(reducer, init).
• Membership / first-match uses array.some / array.find; existence uses array.includes.
• ESLint no-iterator (forbid iterator/__iterator__) is enabled; teams may add no-restricted-syntax to flag plain for over arrays.

Label

Use map / filter / reduce / find over hand-rolled for loops over arrays

PreferFunctionalArrayMethods [rule] v0.1.0

When iterating an array to produce a derived value — a new array, a single accumulator, the first match, a boolean — use the corresponding higher-order method. The named method tells the reader what the loop is for in one word; a for loop with a hand-rolled accumulator buries that intent under index plumbing.

Checks

• Mapping uses array.map(fn), not a for loop pushing into a fresh array.
• Filtering uses array.filter(predicate).
• Aggregating to a scalar uses array.reduce(reducer, init).
• Membership / first-match uses array.some / array.find; existence uses array.includes.
• ESLint no-iterator (forbid iterator/__iterator__) is enabled; teams may add no-restricted-syntax to flag plain for over arrays.

Label

Use map / filter / reduce / find over hand-rolled for loops over arrays

Label

Use map / filter / reduce / find over hand-rolled for loops over arrays