Places in code with 6 or more lines that are exactly the same.
Intro
- For duplication, we look at places in code where there are 6 or more lines of code that are exactly the same.
- Before duplication is calculated, the code is cleaned to remove empty lines, comments, and frequently duplicated constructs such as imports.
- You should aim at having as little as possible (<5%) of duplicated code as high-level of duplication can lead to maintenance difficulties, poor factoring, and logical contradictions.
- To learn more about duplications and techniques for eliminating duplication, Sokrates recommends the following resources:
- Avoid Repetition, MartinFlower.com (IEEE Software article)
- Refactoring duplicated code, sourcemaking.com
- Beck Design Rules, MartinFowler.com
- DRY (Don't Repeat Yourself) Principle, Wikipedia
- The Cut-and-Paste Programming Software Development Anti-Pattern, sourcemaking.com
- Code Smells / Duplicated Code, Jeff Atwood, codinghorror.com:
- "Duplicated code is the bane of software development. Stamp out duplication whenever possible. You should always be on the lookout for more subtle cases of near-duplication, too. Don't Repeat Yourself!"
- Reducing Coupling, MartinFlower.com (IEEE Software article):
- "There are several ways to describe coupling, but it boils down to this: If changing one module in a program requires changing another module, then coupling exists. ... Duplication always implies coupling, because changing one piece of duplicate code implies changing the other."
Duplication Overall
- 59% duplication:
- 90,855 cleaned lines of cleaned code (without empty lines, comments, and frequently duplicated constructs such as imports)
- 54,130 duplicated lines
- 9,921 duplicates
Duplication per Extension
Duplication per Component (primary)
Duplication Between Components (50+ lines)
Open 3D force graph...
Show more details on duplication between components...
From Component
--> To Component
Duplicated
Lines
File Pairs
Details
fixtures/legacy-jsx-runtimes (4%)
--> scripts/jest (12%)
378
2 file pairs
details...
fixtures/dom (3%)
--> scripts/jest (10%)
329
2 file pairs
details...
fixtures/dom (3%)
--> fixtures/legacy-jsx-runtimes (3%)
314
1 file pair
details...
fixtures/legacy-jsx-runtimes (3%)
--> packages/react (5%)
310
32 file pairs
details...
fixtures/legacy-jsx-runtimes (2%)
--> packages/shared (6%)
207
12 file pairs
details...
packages/react-reconciler (<1%)
--> packages/react (2%)
112
8 file pairs
details...
fixtures/ssr (12%)
--> fixtures/ssr2 (9%)
68
3 file pairs
details...
packages/react-devtools-shared (1%)
--> packages/react-devtools-timeline (19%)
65
3 file pairs
details...
fixtures/devtools (2%)
--> packages/react-devtools-shell (15%)
58
2 file pairs
details...
packages/react-dom (14%)
--> packages/react-reconciler (<1%)
55
6 file pairs
details...
| From Component --> To Component |
Duplicated Lines |
File Pairs | Details |
|---|---|---|---|
| fixtures/legacy-jsx-runtimes (4%) --> scripts/jest (12%) |
378 | 2 file pairs | details... |
| fixtures/dom (3%) --> scripts/jest (10%) |
329 | 2 file pairs | details... |
| fixtures/dom (3%) --> fixtures/legacy-jsx-runtimes (3%) |
314 | 1 file pair | details... |
| fixtures/legacy-jsx-runtimes (3%) --> packages/react (5%) |
310 | 32 file pairs | details... |
| fixtures/legacy-jsx-runtimes (2%) --> packages/shared (6%) |
207 | 12 file pairs | details... |
| packages/react-reconciler (<1%) --> packages/react (2%) |
112 | 8 file pairs | details... |
| fixtures/ssr (12%) --> fixtures/ssr2 (9%) |
68 | 3 file pairs | details... |
| packages/react-devtools-shared (1%) --> packages/react-devtools-timeline (19%) |
65 | 3 file pairs | details... |
| fixtures/devtools (2%) --> packages/react-devtools-shell (15%) |
58 | 2 file pairs | details... |
| packages/react-dom (14%) --> packages/react-reconciler (<1%) |
55 | 6 file pairs | details... |
Longest Duplicates
The list of 50 longest duplicates.
| Size | # | Folders | Files | Lines | Code |
|---|---|---|---|---|---|
| 2556 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 261:4049 (92%)261:4049 (92%) | view | |
| 1973 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 165:3151 (94%)165:3151 (94%) | view | |
| 1658 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 247:3130 (90%)247:3130 (90%) | view | |
| 1640 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 1649:3587 (61%)1649:3587 (61%) | view | |
| 943 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 117:1653 (35%)117:1653 (35%) | view | |
| 909 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 46:1402 (98%)46:1402 (98%) | view | |
| 895 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 83:1283 (95%)83:1283 (95%) | view | |
| 881 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 171:1608 (87%)171:1608 (87%) | view | |
| 624 | x 2 | fixtures/legacy-jsx-runtimes/react-17/cjsfixtures/legacy-jsx-runtimes/react-17/cjs | 10:1195 (99%)10:1195 (98%) | view | |
| 548 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 77:872 (92%)77:872 (92%) | view | |
| 537 | x 2 | fixtures/legacy-jsx-runtimes/react-16/cjsfixtures/legacy-jsx-runtimes/react-16/cjs | 10:881 (99%)10:885 (98%) | view | |
| 524 | x 2 | fixtures/legacy-jsx-runtimes/react-15/cjsfixtures/legacy-jsx-runtimes/react-15/cjs | 10:858 (99%)10:862 (98%) | view | |
| 521 | x 2 | fixtures/legacy-jsx-runtimes/react-14/cjsfixtures/legacy-jsx-runtimes/react-14/cjs | 10:853 (99%)10:857 (98%) | view | |
| 517 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 19:873 (99%)19:873 (99%) | view | |
| 501 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 102:790 (88%)102:790 (88%) | view | |
| 468 | x 2 | fixtures/legacy-jsx-runtimes/react-14/cjsfixtures/legacy-jsx-runtimes/react-15/cjs | 100:882 (88%)105:887 (87%) | view | |
| 462 | x 2 | fixtures/legacy-jsx-runtimes/react-14/cjsfixtures/legacy-jsx-runtimes/react-15/cjs | 101:860 (88%)106:865 (87%) | view | |
| 459 | x 2 | fixtures/legacy-jsx-runtimes/react-14/cjsfixtures/legacy-jsx-runtimes/react-15/cjs | 101:853 (87%)105:862 (86%) | view | |
| 459 | x 2 | fixtures/legacy-jsx-runtimes/react-14/cjsfixtures/legacy-jsx-runtimes/react-15/cjs | 100:857 (86%)106:858 (87%) | view | |
| 441 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 84:681 (88%)84:681 (88%) | view | |
| 414 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 36:710 (96%)36:710 (96%) | view | |
| 376 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 117:691 (96%)117:691 (96%) | view | |
| 330 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 37:537 (96%)37:537 (96%) | view | |
| 316 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 27:483 (98%)27:483 (98%) | view | |
| 274 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 13:370 (100%)13:370 (100%) | view | |
| 273 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 90:598 (83%)90:598 (83%) | view | |
| 217 | x 2 | packages/scheduler/src/forkspackages/scheduler/src/forks | 106:422 (57%)89:405 (49%) | view | |
| 214 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 21:341 (100%)21:341 (100%) | view | |
| 170 | x 2 | fixtures/legacy-jsx-runtimesscripts/jest/matchers | 61:303 (83%)27:269 (90%) | view | |
| 140 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 52:242 (88%)52:242 (88%) | view | |
| 137 | x 2 | fixtures/legacy-jsx-runtimes/react-14/cjsfixtures/legacy-jsx-runtimes/react-16/cjs | 646:882 (25%)674:910 (25%) | view | |
| 137 | x 2 | fixtures/legacy-jsx-runtimes/react-15/cjsfixtures/legacy-jsx-runtimes/react-16/cjs | 651:887 (25%)674:910 (25%) | view | |
| 131 | x 2 | fixtures/legacy-jsx-runtimes/react-15/cjsfixtures/legacy-jsx-runtimes/react-16/cjs | 647:865 (24%)670:888 (24%) | view | |
| 131 | x 2 | fixtures/legacy-jsx-runtimes/react-14/cjsfixtures/legacy-jsx-runtimes/react-16/cjs | 642:860 (25%)670:888 (24%) | view | |
| 130 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 13:238 (100%)13:238 (100%) | view | |
| 129 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 12:198 (100%)12:198 (100%) | view | |
| 128 | x 2 | fixtures/legacy-jsx-runtimes/react-15/cjsfixtures/legacy-jsx-runtimes/react-16/cjs | 647:858 (24%)674:885 (23%) | view | |
| 128 | x 2 | fixtures/legacy-jsx-runtimes/react-15/cjsfixtures/legacy-jsx-runtimes/react-16/cjs | 651:862 (24%)670:881 (23%) | view | |
| 128 | x 2 | fixtures/legacy-jsx-runtimes/react-14/cjsfixtures/legacy-jsx-runtimes/react-16/cjs | 642:853 (24%)674:885 (23%) | view | |
| 128 | x 2 | fixtures/legacy-jsx-runtimes/react-14/cjsfixtures/legacy-jsx-runtimes/react-16/cjs | 646:857 (24%)670:881 (23%) | view | |
| 123 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 30:201 (92%)30:201 (92%) | view | |
| 119 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 67:284 (100%)67:284 (100%) | view | |
| 108 | x 2 | fixtures/legacy-jsx-runtimes/react-15/cjsfixtures/legacy-jsx-runtimes/react-16/cjs | 360:499 (20%)381:520 (20%) | view | |
| 108 | x 2 | fixtures/legacy-jsx-runtimes/react-14/cjsfixtures/legacy-jsx-runtimes/react-16/cjs | 359:498 (20%)381:520 (20%) | view | |
| 108 | x 2 | fixtures/legacy-jsx-runtimes/react-14/cjsfixtures/legacy-jsx-runtimes/react-16/cjs | 359:498 (20%)385:524 (19%) | view | |
| 108 | x 2 | fixtures/legacy-jsx-runtimes/react-15/cjsfixtures/legacy-jsx-runtimes/react-16/cjs | 364:503 (20%)385:524 (19%) | view | |
| 108 | x 2 | fixtures/legacy-jsx-runtimes/react-14/cjsfixtures/legacy-jsx-runtimes/react-16/cjs | 355:494 (20%)381:520 (20%) | view | |
| 108 | x 2 | fixtures/legacy-jsx-runtimes/react-14/cjsfixtures/legacy-jsx-runtimes/react-16/cjs | 355:494 (20%)385:524 (19%) | view | |
| 108 | x 2 | fixtures/legacy-jsx-runtimes/react-15/cjsfixtures/legacy-jsx-runtimes/react-16/cjs | 360:499 (20%)385:524 (19%) | view | |
| 108 | x 2 | fixtures/legacy-jsx-runtimes/react-15/cjsfixtures/legacy-jsx-runtimes/react-16/cjs | 364:503 (20%)381:520 (20%) | view |
Duplicated Units
The list of top 50 duplicated units.
| Size | # | Folders | Files | Lines | Code |
|---|---|---|---|---|---|
| 558 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 831:1606 831:1606 | view | |
| 289 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 685:1016 685:1016 | view | |
| 236 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 3774:4047 3774:4047 | view | |
| 224 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 1975:2336 1975:2336 | view | |
| 213 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 2051:2340 2051:2340 | view | |
| 210 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 362:580 362:580 | view | |
| 181 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 1811:2021 1811:2021 | view | |
| 180 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 1676:1891 1676:1891 | view | |
| 157 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 592:768 592:768 | view | |
| 152 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 917:1117 917:1117 | view | |
| 147 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 1093:1275 1093:1275 | view | |
| 145 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 3562:3772 3562:3772 | view | |
| 136 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 457:656 457:656 | view | |
| 135 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 926:1090 926:1090 | view | |
| 119 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 430:596 430:596 | view | |
| 113 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 750:915 750:915 | view | |
| 111 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 754:909 754:909 | view | |
| 110 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 368:550 368:550 | view | |
| 108 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 637:797 637:797 | view | |
| 108 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 1063:1227 1063:1227 | view | |
| 105 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 52:171 52:171 | view | |
| 104 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 1510:1626 1510:1626 | view | |
| 103 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 1080:1204 1080:1204 | view | |
| 112 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 98:225 98:225 | view | |
| 100 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 195:300 195:300 | view | |
| 99 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 3133:3256 3133:3256 | view | |
| 98 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 220:358 220:358 | view | |
| 96 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 393:500 393:500 | view | |
| 94 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 1318:1446 1318:1446 | view | |
| 92 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 2482:2610 2482:2610 | view | |
| 90 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 1208:1306 1208:1306 | view | |
| 89 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 723:849 723:849 | view | |
| 116 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 2198:2350 2198:2350 | view | |
| 87 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 497:593 497:593 | view | |
| 86 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 983:1078 983:1078 | view | |
| 98 | x 2 | fixtures/legacy-jsx-runtimes/react-17/cjsfixtures/legacy-jsx-runtimes/react-17/cjs | 350:501 350:501 | view | |
| 85 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 451:549 451:549 | view | |
| 85 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 2729:2873 2729:2873 | view | |
| 85 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 2672:2773 2672:2773 | view | |
| 83 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 352:449 352:449 | view | |
| 83 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 826:924 826:924 | view | |
| 82 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 1260:1361 1260:1361 | view | |
| 105 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 1665:1792 1665:1792 | view | |
| 80 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 513:632 513:632 | view | |
| 80 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 853:989 853:989 | view | |
| 73 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 374:455 374:455 | view | |
| 70 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 555:630 555:630 | view | |
| 70 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 253:356 253:356 | view | |
| 69 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 652:770 652:770 | view | |
| 68 | x 2 | packages/react-reconciler/srcpackages/react-reconciler/src | 1206:1301 1206:1301 | view |