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Python

#!/usr/bin/env python3
"""Extract a JS/TS project's module-import graph as autolayout graph JSON.
The JavaScript/TypeScript counterpart to pyimports.py: walks a source
directory, scans each module for static and dynamic import specifiers
(`import`/`export ... from`, `require()`, `import()`), keeps only the
intra-project edges (relative specifiers that resolve to a file under the
root), and applies transitive reduction so the diagram stays readable.
python3 jsimports.py src -o graph.json
python3 autolayout.py graph.json -o diagram.drawio
Resolution is path-based: relative specifiers are resolved against the
importing file's directory, trying the .ts/.tsx/.js/.jsx/.mjs/.cjs extensions
and directory index files. Bare specifiers (node_modules packages such as
"react") are ignored. Scanning is regex-based rather than a full parser, so a
specifier inside a comment or string literal is counted in rare cases.
Usage: python3 jsimports.py <src_dir> [-o graph.json] [--direction TB|LR]
[--group] [--no-reduce]
"""
import argparse
import json
import os
import re
import subprocess
import sys
EXTS = (".ts", ".tsx", ".js", ".jsx", ".mjs", ".cjs")
SPEC = re.compile(
r"(?:import|export)\b[^'\";]*?\bfrom\s*['\"]([^'\"]+)['\"]" # import/export ... from "x"
r"|import\s*['\"]([^'\"]+)['\"]" # import "x" (side effect)
r"|require\s*\(\s*['\"]([^'\"]+)['\"]\s*\)" # require("x")
r"|import\s*\(\s*['\"]([^'\"]+)['\"]\s*\)" # import("x") dynamic
)
def modid(path, root):
"""Module id = path relative to root, extension stripped, posix separators."""
rel = os.path.relpath(path, root)
for ext in EXTS:
if rel.endswith(ext):
rel = rel[: -len(ext)]
break
return rel.replace(os.sep, "/")
def discover(root):
"""Map module id -> absolute file path for every source file under root."""
root = os.path.abspath(root)
modules = {}
for dirpath, dirs, files in os.walk(root):
dirs[:] = [d for d in dirs if d != "node_modules" and not d.startswith(".")]
for fn in files:
if fn.endswith(EXTS) and not fn.endswith(".d.ts"):
full = os.path.join(dirpath, fn)
modules[modid(full, root)] = full
return modules, root
def resolve(spec, importer, root, modules):
"""Resolve a relative specifier to a known module id, or None (external)."""
if not spec.startswith("."):
return None
base = os.path.normpath(os.path.join(os.path.dirname(importer), spec))
candidates = ([base + e for e in EXTS]
+ [os.path.join(base, "index" + e) for e in EXTS]
+ [base])
for cand in candidates:
mid = modid(cand, root)
if mid in modules and modules[mid] != importer:
return mid
return None
def edges_of(mid, path, root, modules):
"""Intra-project modules imported by module `mid`."""
found = set()
try:
with open(path, encoding="utf-8", errors="ignore") as f:
src = f.read()
except OSError:
return found
for m in SPEC.finditer(src):
spec = m.group(1) or m.group(2) or m.group(3) or m.group(4)
target = resolve(spec, path, root, modules)
if target and target != mid:
found.add(target)
return found
def transitive_reduce(nodes, edges):
"""Drop edges implied by a longer path, via Graphviz `tred`."""
idx = {n: i for i, n in enumerate(nodes)}
dot = "digraph{" + "".join(f"{idx[s]}->{idx[t]};" for s, t in edges) + "}"
try:
out = subprocess.run(["tred"], input=dot, capture_output=True,
text=True, check=True).stdout
except (FileNotFoundError, subprocess.CalledProcessError) as exc:
sys.stderr.write(f"warning: tred unavailable, keeping all edges ({exc})\n")
return edges
rev = {i: n for n, i in idx.items()}
return [(rev[int(a)], rev[int(b)]) for a, b in re.findall(r"(\d+)\s*->\s*(\d+)", out)]
def common_dir(ids):
"""Longest shared leading path segment across module ids (e.g. 'src/')."""
common = []
for parts in zip(*[m.split("/") for m in ids]):
if len(set(parts)) == 1:
common.append(parts[0])
else:
break
return "/".join(common) + "/" if common else ""
def main():
ap = argparse.ArgumentParser(description="JS/TS import graph -> autolayout graph JSON.")
ap.add_argument("src", help="source directory")
ap.add_argument("-o", "--output", help="output JSON path (default: stdout)")
ap.add_argument("--direction", default="TB", choices=["TB", "LR"])
ap.add_argument("--group", action="store_true",
help="group nodes into containers by top-level directory")
ap.add_argument("--no-reduce", action="store_true",
help="keep every edge (skip transitive reduction)")
args = ap.parse_args()
modules, root = discover(args.src)
if not modules:
sys.exit(f"error: no JS/TS modules found under {args.src}")
edges = sorted({(m, t) for m, p in modules.items()
for t in edges_of(m, p, root, modules)})
raw = len(edges)
if not args.no_reduce:
edges = transitive_reduce(list(modules), edges)
strip = common_dir(list(modules))
label = lambda m: (m[len(strip):] if strip and m.startswith(strip) else m) or m
def node(m):
d = {"id": m, "label": label(m)}
if args.group:
rest = label(m).split("/")
if len(rest) > 1: # has a sub-directory
d["group"] = "/".join(rest[:-1]) # full directory path -> nested boxes
return d
graph = {
"direction": args.direction,
"nodes": [node(m) for m in modules],
"edges": [{"source": s, "target": t} for s, t in edges],
}
text = json.dumps(graph, indent=2)
if args.output:
with open(args.output, "w", encoding="utf-8") as f:
f.write(text)
sys.stderr.write(f"wrote {args.output}\n")
else:
sys.stdout.write(text)
note = "" if args.no_reduce else f" (reduced from {raw})"
sys.stderr.write(f"{len(modules)} modules, {len(edges)} edges{note}\n")
if __name__ == "__main__":
main()