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How to migrate parserOptions to ESLint flat config

Move parserOptions into languageOptions.parserOptions in flat config.

Start here

The safe first move

Move parserOptions settings like ecmaVersion and sourceType into languageOptions.

Stop before automation when: Custom parser configurations beyond standard options. TypeScript parser settings that need @typescript-eslint/parser.

Target shape

module.exports = [{
  languageOptions: {
    ecmaVersion: 2022,
    sourceType: "module",
  },
}];

Repo fit check

Want to know if your repo has this pattern?

Run the matching scanner locally first. The fit-report add-on is not listed for this proof-only product yet, so use the proof page and scanner output before treating it as a purchase candidate.

  • Local scan; no repository upload.
  • Supported findings are separated from manual-review findings.
  • Buy only when the repeated pattern is worth automating.
Run the static-config scan View example report See when to buy 
Example scan summary
supported_findings: 38
manual_review_findings: 6
files_uploaded: 0
confidence: reviewable

Why this page exists

How to migrate parserOptions to ESLint flat config

parserOptions moves into languageOptions in flat config.

Direct answer

What changes

Move parserOptions settings like ecmaVersion and sourceType into languageOptions.

Example

Before and after

Before

{
  "parserOptions": {
    "ecmaVersion": 2022,
    "sourceType": "module"
  }
}

After

module.exports = [{
  languageOptions: {
    ecmaVersion: 2022,
    sourceType: "module",
  },
}];

Decision path

If this repeats across the repo, open the evaluation pages next.

This product exists for the static-config subset. It does not pretend to evaluate JS config logic.

  • Teams migrating static .eslintrc JSON or YAML configs.
  • Repos that still store eslintConfig inside package.json.
  • The fit-report add-on is not listed for this proof-only product yet; use the proof page and scanner output before treating this as purchasable.

Before checkout

Product fit, proof, and price should all be one click away.

Current listed price is not published on the pricing page yet.

Typical symptoms

  • Legacy config sets ecmaVersion and sourceType in parserOptions.
  • Teams need parser settings preserved in the flat config bridge.
  • FlatCompat can carry these through automatically.

What the product covers

  • Static parserOptions in JSON/YAML configs.
  • ecmaVersion and sourceType migration.
  • Integration with FlatCompat bridge generation.

Manual-review boundary

  • Custom parser configurations beyond standard options.
  • TypeScript parser settings that need @typescript-eslint/parser.
  • Repos with JS-backed parser logic.

Keep the migration narrow

Use the exact-problem guides as a triage layer, then decide whether the repo is inside the supported subset.

FAQ

Fast answers before you decide

What is the safest fix for eslint parserOptions flat config?

Move parserOptions settings like ecmaVersion and sourceType into languageOptions.

Can eslint parserOptions flat config be automated?

Automate only the supported subset: Static parserOptions in JSON/YAML configs. ecmaVersion and sourceType migration. Integration with FlatCompat bridge generation. Keep these cases in manual review: Custom parser configurations beyond standard options. TypeScript parser settings that need @typescript-eslint/parser. Repos with JS-backed parser logic.

When should I buy ESLint Flat Config Migration Cleanup Pack?

Use ESLint Flat Config Migration Cleanup Pack only when this pattern repeats across enough files that manual cleanup is still costly. Run the public scan or read the proof first. The fit-report add-on is not listed for this proof-only product yet; if unsupported findings dominate, keep the work manual.