• There are 622 files with units, with 57,209 lines of code.
• 8 very complex files (McCabe index sum 251+; 21,146 lines of code)
• 8 complex files (McCabe index sum 126-250; 4,825 lines of code)
• 31 medium complex files (McCabe index sum 51-125; 8,757 lines of code)
• 41 slightly complex files (McCabe index sum 26-50; 6,431 lines of code)
• 534 simple files (McCabe index sum 1-25; 16,050 lines of code)
• 860 main files have no units (e.g. languages without unit analysis, or files without functions) and are not classified.

The McCabe index of a file grows with its size: per 100 lines tells a large but plain file from a dense one, and most complex unit whether the complexity sits in one unit or is spread over many.

File	# lines	# units	McCabe index (sum)	per 100 lines	most complex unit
system.src.js in jspm_packages	3440	232	2223	65	1059
system-csp-production.src.js in jspm_packages	2991	205	1917	64	903
core.js in jspm_packages/npm/core-js@1.2.6/client	3804	303	921	24	22
library.js in jspm_packages/npm/core-js@1.2.6/client	3438	277	851	25	23
shim.js in jspm_packages/npm/core-js@1.2.6/client	3508	272	850	24	22
iscroll.js in harness/app-assets/templates/assets/js/components	1565	80	502	32	36
iscroll.js in build/app-assets/templates/assets/js/components	1565	80	502	32	36
curl.js in harness	835	77	256	31	20
system-polyfills.src.js in jspm_packages	770	120	233	30	20
index.js in jspm_packages/npm/buffer@3.6.0	1201	48	214	18	24
reqwest.js in jspm_packages/github/ded/reqwest@1.1.5	477	47	201	42	18
common.js in harness/app-assets/templates/assets/js/bootstraps	585	46	140	24	16
common.js in build/app-assets/templates/assets/js/bootstraps	585	46	140	24	16
util.js in jspm_packages/npm/util@0.10.3	423	36	135	32	31
runtime.js in jspm_packages/npm/babel-runtime@5.8.38/regenerator	434	34	134	31	26
external-helpers.js in jspm_packages/npm/babel-core@5.8.38	350	28	126	36	26
assert.js in jspm_packages/npm/assert@1.4.0	302	20	125	41	25
es5.js in jspm_packages/npm/core-js@1.2.6/library/modules	250	25	111	44	11
es5.js in jspm_packages/npm/core-js@1.2.6/modules	250	25	111	44	11
flipsnap.js in harness/app-assets/templates/assets/js/components	463	31	110	24	12
flipsnap.js in build/app-assets/templates/assets/js/components	463	31	110	24	12
liveblog.js in harness/app-assets/templates/assets/js/bootstraps	463	34	106	23	9
liveblog.js in build/app-assets/templates/assets/js/bootstraps	463	34	106	23	9
introspection.js in jspm_packages/npm/babel-core@5.8.38/lib/traversal/path	229	16	94	41	24
$.buffer.js in jspm_packages/npm/core-js@1.2.6/library/modules	294	41	88	30	18
$.buffer.js in jspm_packages/npm/core-js@1.2.6/modules	294	41	88	30	18
es6.promise.js in jspm_packages/npm/core-js@1.2.6/library/modules	304	27	84	28	8
es6.promise.js in jspm_packages/npm/core-js@1.2.6/modules	304	27	84	28	8
quiz.js in harness/app-assets/templates/assets/js/modules	398	26	78	20	9
quiz.js in build/app-assets/templates/assets/js/modules	398	26	78	20	9
converters.js in jspm_packages/npm/babel-core@5.8.38/lib/types	222	10	74	33	18
block-scoping.js in jspm_packages/npm/babel-core@5.8.38/lib/transformation/transformers/es6	450	19	68	15	11
context.js in jspm_packages/npm/babel-core@5.8.38/lib/traversal/path	181	18	65	36	13
iframeMessenger.js in jspm_packages/github/guardian/iframe-messenger@master/src	276	25	64	23	9
validators.js in jspm_packages/npm/babel-core@5.8.38/lib/types	139	9	62	45	33
index.js in jspm_packages/npm/babel-core@5.8.38/lib/types	270	19	60	22	13
$.typed-array.js in jspm_packages/npm/core-js@1.2.6/library/modules	306	34	60	20	5
$.typed-array.js in jspm_packages/npm/core-js@1.2.6/modules	306	34	60	20	5
parentheses.js in jspm_packages/npm/babel-core@5.8.38/lib/generation/node	137	12	57	42	12
visitors.js in jspm_packages/npm/babel-core@5.8.38/lib/traversal	147	8	56	38	20
flow.js in jspm_packages/npm/babel-core@5.8.38/lib/generation/generators	265	38	56	21	6
whitespace.js in jspm_packages/npm/babel-core@5.8.38/lib/generation/node	143	15	55	38	11
ads.js in harness/app-assets/templates/assets/js/modules	226	19	53	23	9
comments.js in harness/app-assets/templates/assets/js/modules	220	16	53	24	8
ads.js in build/app-assets/templates/assets/js/modules	226	19	53	23	9
comments.js in build/app-assets/templates/assets/js/modules	220	16	53	24	8
index.js in jspm_packages/npm/path-browserify@0.0.0	148	14	51	34	8
util.js in jspm_packages/npm/babel-core@5.8.38/lib	184	12	49	27	8
expressions.js in jspm_packages/npm/babel-core@5.8.38/lib/generation/generators	201	18	47	23	12
$.collection-strong.js in jspm_packages/npm/core-js@1.2.6/library/modules	153	11	46	30	9

• File complexity is the sum of the McCabe indexes (conditional complexity) of the units (methods, functions...) in a file.
• Files are classified in five categories based on that sum: 1-25 (simple files), 26-50 (slightly complex files), 51-125 (medium complex files), 126-250 (complex files), 251+ (very complex files). The default bands are five times the unit complexity bands, as a file is a group of units.
• Only main code files with units are classified. Files without units (languages without unit analysis, or files without functions) have no complexity to measure and are left out rather than counted as simple.
• A very complex file holds many decisions, which often means it has too many responsibilities: a candidate to split, and a place where changes need more testing.