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Analyze your project for dead code. Fallow scans entry points, traces all reachable exports, and reports anything that isn’t used.
This is the default command. Running fallow is equivalent to fallow check.
fallow check
fallow        # Same as fallow check

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Options

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Output

FlagDescription
-f, --format <FORMAT>Output format: human (default), json, sarif, compact
--quietSuppress progress output
--fail-on-issuesPromote all warn rules to error
--ciCI mode: sets format to SARIF, enables fail-on-issues, suppresses progress. Individual flags can still override.

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Filtering

FlagDescription
--unused-filesOnly report unused files
--unused-exportsOnly report unused exports
--unused-typesOnly report unused types
--unused-depsOnly report unused dependencies
--unused-enum-membersOnly report unused enum members
--unused-class-membersOnly report unused class members
--unresolved-importsOnly report unresolved imports
--unlisted-depsOnly report unlisted dependencies
--duplicate-exportsOnly report duplicate exports

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Incremental

FlagDescription
--changed-since <REF>Only check files changed since a git ref
--baselineCompare against saved baseline
--save-baselineSave current issues as baseline
--productionProduction mode (exclude test/dev files)
These flags help you understand how fallow resolves your code and where time is spent.
FlagDescription
--trace <FILE:EXPORT>Trace usage of a specific export
--trace-file <PATH>Show all edges for a file
--trace-dependency <PACKAGE>Show where a dependency is used
--performanceShow pipeline timing breakdown
# Why is formatDate reported as unused?
fallow check --trace src/utils.ts:formatDate

# What imports/exports does this file have?
fallow check --trace-file src/utils.ts

# Where is lodash used?
fallow check --trace-dependency lodash

# Pipeline performance breakdown
fallow check --performance

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Examples

fallow check

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Example output

$ fallow check --format compact
unused-file:src/server/jobs/worker.ts
unused-file:src/features/savings/hooks/usePotGroups.ts
unused-file:src/server/jobs/cron.ts
unused-export:src/server/jobs/queue.ts:61:enqueueJobDelayed
unused-export:src/server/jobs/queue.ts:206:sweepStuckProcessingJobs
unused-export:src/components/Card/index.ts:1:CardFooter

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See also

Dead code analysis

How fallow detects dead code.

Rules configuration

Configure severity and thresholds per rule.

Production mode

Analyze only shipping code.