Configuration

The configuration file is considered optional, Rome has good defaults. Use the configuration file to change those defaults.

The Rome configuration file is named rome.json and should be placed in the root directory of your project. The root directory is usually the directory containing your project’s package.json.

Here’s an example:

rome.json

{
  "formatter": {
    "enabled": true,
    "indentStyle": "tab",
    "lineWidth": 120
  },
  "linter": {
    "enabled": false
  }
}

This configuration file enables the formatter and sets the preferred indent style and width. The linter is disabled.

`$schema`

Allows to pass a path to a JSON schema file.

Since version 11.0.0, a JSON schema file for the rome.json is published.

You can specify a relative path to the schema of the rome npm package if rome is installed in the node_modules folder:

rome.json

{
  "$schema": "./node_modules/rome/configuration_schema.json"
}

`files`

`files.maxSize`

The maximum allowed size for source code files in bytes. Files above this limit will be ignored for performance reason.

Default: 1024*1024 (1MB)

`files.ignore`

A list of Unix shell style patterns. Rome ignores files and folders that match these patterns.

rome.json

{
  "files": {
    "ignore": ["scripts/*.js"]
  }
}

`linter`

`linter.enabled`

Enables Rome’s linter

Default: true

`linter.ignore`

An array of Unix shell style patterns.

rome.json

{
  "linter": {
    "ignore": ["scripts/*.js"]
  }
}

`linter.rules.recommended`

Enables the recommended rules for all categories.

Default: true

`linter.rules.[category]`

Options that influence the rules of a single category. Rome supports the following categories:

- `Accessibility`: Rules focused on preventing accessibility problems. - `Complexity`: Rules that focus on inspecting complex code that could be simplified. - `Correctness`: Rules that detect incorrect or useless code. - `Security`: Rules that detect potential security flaws. - `Style`: Rules enforcing a consistent way of writing your code. - `Nursery`: New rules that are still under development. Nursery rules require explicit opt-in via configuration because they may still have bugs or performance problems. Nursery rules get promoted to other groups once they become stable or may be removed. Rules that belong to this group are not subject to semantic version.

`linter.rules.[category].recommended`

Enables the recommended rules for a single category.

Example:

rome.json

{
  "linter": {
    "enabled": true,
    "rules": {
      "nursery": {
        "recommended": true
      }
    }
  }
}

`formatter`

These options apply to all languages. There are additional language-specific formatting options below.

`formatter.enabled`

Enables Rome’s formatter

Default: true

`formatter.ignore`

An array of Unix shell style patterns.

rome.json

{
  "formatter": {
    "ignore": ["scripts/*.js"]
  }
}

`formatter.formatWithErrors`

Allows to format a document that has syntax errors.

rome.json

{
  "formatter": {
    "formatWithErrors": true
  }
}

Default: false

`formatter.indentStyle`

The style of the indentation. It can be "tab" or "space".

Default: tab

Rome’s default is "tab".

`formatter.indentSize`

How big the indentation should be.

Default: 2

`formatter.lineWidth`

How many characters can be written on a single line.

Default: 80

`javascript`

These options apply only to JavaScript (and TypeScript) files.

`javascript.formatter.quoteStyle`

The type of quote used when representing string literals. It can be single or double.

Default: double

`javascript.formatter.quoteProperties`

When properties inside objects should be quoted. It can be asNeeded or preserve.

Default: asNeeded

`javascript.formatter.trailingComma`

Print trailing commas wherever possible in multi-line comma-separated syntactic structures. Possible values:

all, the trailing comma is always added
es5, the trailing comma is added only in places where it’s supported by older version of JavaScript
none, trailing commas are never added

Default: all

`javascript.formatter.semicolons`

It configures where the formatter prints semicolons:

always, the semicolons is always added at the end of each statement;
asNeeded, the semicolons are added only in places where it’s needed, to protect from ASI

Default: always

Example:

rome.json

{
  "javascript": {
    "formatter": {
      "semicolons": "asNeeded"
    }
  }
}