Rollup Config Validator

Validate Rollup config files (rollup.config.js/mjs/ts) for output format conflicts, plugin ordering issues, deprecated options, and best practices. Use when validating Rollup bundler configs, auditing build pipelines, migrating Rollup versions, or linting rollup config files.

Validate Rollup config files (exported JSON or parsed config objects) for output format conflicts, external/bundle mismatches, plugin ordering issues, deprecated options, treeshake settings, and best practices. Supports text, JSON, and summary output formats with CI-friendly exit codes.

Commands

bash

# Full validation (all 22+ rules)
python3 scripts/rollup_config_validator.py validate rollup.config.json

# Quick syntax-only check (structure rules only)
python3 scripts/rollup_config_validator.py check rollup.config.json

# Explain config in human-readable form
python3 scripts/rollup_config_validator.py explain rollup.config.json

# Suggest improvements
python3 scripts/rollup_config_validator.py suggest rollup.config.json

# JSON output (CI-friendly)
python3 scripts/rollup_config_validator.py validate rollup.config.json --format json

# Summary only (pass/fail + counts)
python3 scripts/rollup_config_validator.py validate rollup.config.json --format summary

# Strict mode (warnings become errors)
python3 scripts/rollup_config_validator.py validate rollup.config.json --strict

Input Format

Since Rollup configs are typically JavaScript, this tool validates JSON representations of Rollup config objects. Export your config as JSON or use a wrapper:

bash

# Extract config as JSON from rollup.config.js
node -e "const c = require('./rollup.config.js'); console.log(JSON.stringify(c, null, 2))" > rollup.config.json
python3 scripts/rollup_config_validator.py validate rollup.config.json

Or validate directly from a JSON config file.

Rules (22+)

#	Category	Severity	Rule
S1	Structure	Error	File not found or unreadable
S2	Structure	Error	Empty config or no content
S3	Structure	Warning	Unknown top-level config keys
S4	Structure	Error	Invalid JSON syntax
S5	Structure	Error	Missing input entry point
O1	Output	Error	Missing output configuration
O2	Output	Warning	Missing output.format (defaults to 'es')
O3	Output	Warning	output.file and output.dir both specified
O4	Output	Warning	format: 'iife' or 'umd' without output.name
O5	Output	Warning	Multiple outputs with same format and no distinct file/dir
O6	Output	Warning	output.sourcemap: true without sourcemapExcludeSources consideration
E1	External	Warning	Bare module in external should match import pattern
E2	External	Warning	Regex pattern in external (fragile)
E3	External	Warning	Node built-in not in external (path, fs, etc.)
P1	Plugins	Warning	Plugin ordering: resolve before commonjs
P2	Plugins	Warning	commonjs plugin without @rollup/plugin-node-resolve
P3	Plugins	Warning	json plugin missing (importing .json files)
P4	Plugins	Warning	Deprecated plugin (rollup-plugin-* → @rollup/plugin-*)
T1	Treeshake	Warning	treeshake: false disables dead code elimination
T2	Treeshake	Warning	moduleSideEffects: false may break libraries
B1	Best Practices	Warning	Missing preserveEntrySignatures for library builds
B2	Best Practices	Warning	Large number of manual chunks without shared dependencies
B3	Best Practices	Warning	watch mode config without clearScreen setting

Output Formats

• text (default): Human-readable with severity icons
• json: Machine-parseable JSON array of findings
• summary: Pass/fail with error/warning counts

Exit Codes

• 0: No errors (warnings only or clean)
• 1: One or more errors found
• 2: File not found or invalid input

Requirements

• Python 3.8+
• No external dependencies (pure stdlib)