No filter().map() Chain

Suggestion

small-rules/no-filter-map-chain

Disallow map(...) directly after filter(...).

Diagnostic Messages

avoidFilterMapChain

Do not chain map(...) directly after filter(...). Combine both operations in a single loop.

Configuration

This rule does not accept options.

{
  "jsPlugins": [
    "@pobammer-ts/small-rules"
  ],
  "rules": {
    "small-rules/no-filter-map-chain": "error"
  }
}

Examples

filter followed by map

const baseArray = [1, 2, 3, 4, 5, 6, 7];
const array = baseArray
  .filter((value) => value % 2 === 0)
  .map((value) => value * 2);

single-pass filtering and mapping

const baseArray = [1, 2, 3, 4, 5, 6, 7];
const filteredArray = new Array<number>();
for (const value of baseArray) {
  if (value % 2 !== 0) continue;
  filteredArray.push(value * 2);
}