analyze-bundle

name	analyze-bundle
description	Convert Next.js bundle analyzer data to NDJSON and explore it
allowed-tools	Bash(node *) Bash(head:*) Bash(tail:*) Bash(grep:*) Bash(jq:*) Read

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)'