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consistent-source-extension

Require consistent import/export source paths without file extensions.

Targeted pattern scope​

This rule reports string-literal module sources that end with these explicit extensions:

  • .js
  • .json
  • .ts

It applies to import/export sources and any matching source literal in supported module syntax nodes.

What this rule reports​

This rule reports import/export paths that end with .js, .json, or .ts.

Why this rule exists​

Teams that standardize extensionless internal specifiers use this rule to keep import/export declarations consistent.

❌ Incorrect​

import x1 from "source.js";
import x2 from "source.json";
import x3 from "source.ts";

✅ Correct​

import x1 from "source";
import x2 from "source";
import x3 from "source";

Deprecated​

  • Lifecycle: Deprecated and frozen.
  • Deprecated since: v1.0.0
  • Available until: v2.0.0
  • Use instead: import/extensions

Behavior and migration notes​

This rule is deprecated in favor of import/extensions.

It reports only and does not provide an autofix.

Options​

This rule has no options.

Status​

Use the Deprecated section above for lifecycle details.

Additional examples​

export * from "./utils.ts";
// ❌ reported

export * from "./utils";
// ✅ valid

ESLint flat config example​

import etcMisc from "eslint-plugin-etc-misc";

export default [
 {
  plugins: { "etc-misc": etcMisc },
  rules: {
   "etc-misc/consistent-source-extension": "error",
  },
 },
];

When not to use it​

Disable this rule if your module resolver requires explicit source file extensions.

Package documentation​

Rule catalog ID: R009

Further reading​

Adoption resources​

  • Start at warning level in CI, then move to error after cleanup.
  • Use focused codemods/autofix batches per package or directory.