no-banned-imports

Prevent usage of banned libraries and enforce recommended alternatives.

Rule details

Teams often ban heavy or deprecated libraries in favor of lighter or native alternatives. This rule uses a data-driven configuration — an array of objects specifying the regex pattern, the library name, and the recommended alternative. Adding a new ban is a one-line change.

Examples of incorrect code

src/utils/date.ts

import { format } from "moment";

src/api/client.ts

import axios from "axios";

Examples of correct code

src/utils/date.ts

import { format } from "date-fns";

src/api/client.ts

const response = await fetch("/api/data");

Rule implementation

/// <reference path="../rules.d.ts" />

const BANNED_IMPORTS = [
  {
    pattern: /from\s+['"]lodash['"]/,
    name: "lodash",
    alternative: "native array methods",
  },
  {
    pattern: /from\s+['"]moment['"]/,
    name: "moment",
    alternative: "Temporal API or date-fns",
  },
  {
    pattern: /from\s+['"]axios['"]/,
    name: "axios",
    alternative: "native fetch()",
  },
];

export default {
  rules: {
    "no-banned-imports": {
      description: "Prevent usage of banned libraries",
      async check(ctx) {
        for (const banned of BANNED_IMPORTS) {
          const matches = await ctx.grepFiles(banned.pattern, "src/**/*.ts");
          for (const match of matches) {
            ctx.report.violation({
              message: `Banned import: "${banned.name}" is not allowed. Use ${banned.alternative} instead.`,
              file: match.file,
              line: match.line,
              fix: `Replace ${banned.name} with ${banned.alternative}`,
            });
          }
        }
      },
    },
  },
} satisfies RuleSet;

When to use it

When your team has standardized on specific libraries and wants to prevent drift toward alternatives. Common bans include lodash (native methods), moment (date-fns or Temporal), and axios (native fetch).

When not to use it

When your project has no preference between libraries, or when the banned library is still in active migration and some usage is expected temporarily.