fallow migrate

CLI reference for fallow migrate. Automatically convert your existing knip or jscpd configuration to fallow’s config format.

Auto-migrate your existing knip and/or jscpd configuration to fallow. The migrate command reads your current config, translates it to fallow’s format, and writes a new config file.

If both knip and jscpd configs exist in your project, fallow merges them into a single unified config.

Use --dry-run to preview the generated config before writing anything to disk.

fallow migrate

Options

Flag	Description
--toml	Output as fallow.toml (mutually exclusive with --jsonc)
--jsonc	Write to .fallowrc.jsonc instead of .fallowrc.json. The generated content is the same JSONC (with // comments) either way; the .jsonc extension lets editors auto-detect JSON-with-comments syntax highlighting and silences linters that flag comments in .json
--dry-run	Preview the generated config without writing
--from <PATH>	Path to the config file to migrate

Without --jsonc or --toml, fallow auto-mirrors the source extension: a knip.jsonc migration writes .fallowrc.jsonc, a knip.json migration writes .fallowrc.json. The fallow config parser accepts comments in both extensions.

What it detects

Fallow auto-detects:

• knip.json, knip.jsonc, .knip.json, .knip.jsonc, knip.ts, knip.config.ts
• knip field in package.json

TypeScript config files (knip.ts, knip.config.ts) are detected but cannot be parsed. Convert to knip.json first, then re-run migrate.

• .jscpd.json
• jscpd field in package.json

Examples

Auto-detect

# Detect config files and migrate
fallow migrate

# Preview without writing
fallow migrate --dry-run

Warnings are shown for any config fields that can’t be migrated automatically.

See also

Migrating from knip

Detailed comparison and migration guide from knip.

Migrating from jscpd

Detailed comparison and migration guide from jscpd.