analyze-bundle

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Convert Next.js bundle analyzer data to NDJSON and explore it

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How to use this skill

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I want to install this Agent Skill for this project in Codex.

Source SKILL.md: https://github.com/vercel-labs/dev3000/blob/HEAD/.agents/skills/analyze-bundle/SKILL.md

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analyze-to-ndjson

Converts Next.js bundle analyzer binary .data files into grep/jq-friendly NDJSON.

Analyze artifacts

This workflow pre-generates analyzer artifacts in:

.next/diagnostics/analyze/ndjson/routes.ndjson
.next/diagnostics/analyze/ndjson/sources.ndjson
.next/diagnostics/analyze/ndjson/output_files.ndjson
.next/diagnostics/analyze/ndjson/module_edges.ndjson
.next/diagnostics/analyze/ndjson/modules.ndjson

Focus on reading these files and using their evidence to prioritize changes.

Output files

File	What's in it
`modules.ndjson`	Global module registry (`id`, `ident`, `path`)
`module_edges.ndjson`	Module dependency graph (`from`, `to`, `kind`: sync/async)
`sources.ndjson`	Per-route source tree with sizes and environment flags
`chunk_parts.ndjson`	Granular size data: one line per (source, output_file) pair
`output_files.ndjson`	Per-route output files with aggregated sizes
`routes.ndjson`	Route-level summaries

Browsing the output

Route overview

jq -s 'sort_by(-.total_compressed_size)' .next/diagnostics/analyze/ndjson/routes.ndjson

Find large sources

jq -s '
  group_by(.full_path)
  | map(max_by(.compressed_size))
  | sort_by(-.compressed_size)
  | .[0:10]
  | .[] | {full_path, compressed_size, size, route}
' .next/diagnostics/analyze/ndjson/sources.ndjson

Client-side JS

grep '"client":true' .next/diagnostics/analyze/ndjson/sources.ndjson \
  | grep '"js":true' \
  | jq -s 'sort_by(-.compressed_size) | .[0:10] | .[] | {full_path, compressed_size}'

Module dependencies

grep '"from":42,' .next/diagnostics/analyze/ndjson/module_edges.ndjson | jq .to
grep '"to":42,' .next/diagnostics/analyze/ndjson/module_edges.ndjson | jq .from
grep 'react-dom' .next/diagnostics/analyze/ndjson/modules.ndjson | jq '{id, path}'

Output files for a route

grep '"route":"/"' .next/diagnostics/analyze/ndjson/output_files.ndjson \
  | jq -s 'sort_by(-.total_compressed_size) | .[0:10] | .[] | {filename, total_compressed_size, num_parts}'

Directory tree for a route

grep '"route":"/"' .next/diagnostics/analyze/ndjson/sources.ndjson \
  | jq 'select(.parent_id == null)'