Performance Plugin

Rules for specialized code designed specifically to be run in performance-critical "hot paths".
This plugin is provided in a standalone @flint.fyi/plugin-performance npm package.

npm

npm install @flint.fyi/plugin-performance

pnpm

pnpm install @flint.fyi/plugin-performance

yarn

yarn install @flint.fyi/plugin-performance

Presets

Flint’s performance plugin provides the following preset:

Preset	Recommended	Description
logical	✅ Always	Common rules for finding bugs and good practices for high-performance code.

Flint recommends using the logical preset:

flint.config.ts

import { performance } from "@flint.fyi/performance";
import { defineConfig } from "flint";

export default defineConfig({
  use: [
    {
      files: performance.files.all,
      rules: [performance.presets.logical],
    },
  ],
});

Note

Coming soon: more expansive documentation on choosing and combining plugins & presets with Flint.

logical

Rules that find bugs and enforce good performance practices and catch common pitfalls for most-to-all JavaScript and TypeScript files.

flint.config.ts

import { performance } from "@flint.fyi/performance";
import { defineConfig } from "flint";

export default defineConfig({
  use: [
    {
      files: performance.files.all,
      rules: performance.presets.logical,
    },
  ],
});

Rules

Flint Rule	Preset
deletesReports using the delete operator.	logical
importedNamespaceDynamicAccessesDisallow computed member access on imported namespace identifiers.	logical
loopAwaitsReports using await expressions inside loops.	logical
loopFunctionsReports function declarations and expressions inside loops that reference variables modified by the loop.	logical
spreadAccumulatorsReports spread operations that accumulate values in loops, causing quadratic time complexity.	logical