Only 39% of the functions in node_modules are unique in the default Angular project

21 мин

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Only 39% of the functions in node_modules are unique in the default Angular project created by ng new my-app.

I think the developers of open source solve problems in the same ways, because they study the same algorithms. Well, why be honest, they copy the popular solutions from StackOverflow also.

How to compare functions in Javascript?

If you want to compare functions in Javascript, then just convert them to string form:

const a = () => 'hi';
a.toString(); // "() => 'hi'"

If variable names are different

It is necessary to bring them to the same form using the UglifyJs library. UglifyJs will minimizes functions, remove unnecessary strings, and make simple calculations.

For this I used the Esprima library. We parse the file and walk an AST tree. I think that it would be possible only with Uglifyjs, but something was wrong and I was too lazy to figure it out.

Action plan

Iterate through all the * .js files in the directory
Parse each file and extract functions of types ArrowFunctionExpression,FunctionExpression and FunctionDeclaration
Compress each of the functions using UglifyJs and write it to a file whose name is the hash of the function
Put the id, path and hash to the separate file info.csv
Load the file info.csv intoSQLite and make all kinds of queries, because this database is not a toy!

Implementation details

I named all arrow functions and functional expressions z;
I renamed the usual functions to MORK, but kept the original names separately, because the function may be the same, but have a different name;
Perhaps with these renames I lost some of the statistics related to recursive functions, well, okay!

Listing of the file from which we will extract functions:

(function () {
    const arbuz = (test) => {
        function apple(t) {
            function test () {
                return 'ttt';
            }
            return t + 3;
        }
        const aa = 1;
        const b1 = () => 2;
        // comment
        return aa + b1() + apple(test);
    }
    return arbuz;
 })();

Note that some of the expressions are calculated, that's comfortable for function comparing. The list of the extracted functions:

"const z=function(){return n=>{return 3+(n+3)}};";
"const z=n=>{return 3+(n+3)};";
"function MORK(n){return n+3}";
"function MORK(){return"ttt"}";
"const z=()=>2;";

Full script can be found here

First research object: `node_modules` of the default Angular 11 project

So, we have to create a project using @angular/cli: ng new my-app and run our script to parse node_modules. It can take a lot of time.

View package.json

{
  "name": "my-app",
  "version": "0.0.0",
  "scripts": {
    "ng": "ng",
    "start": "ng serve",
    "build": "ng build --prod",
    "test": "ng test",
    "lint": "ng lint",
    "e2e": "ng e2e"
  },
  "private": true,
  "dependencies": {
    "@angular/animations": "~11.2.10",
    "@angular/common": "~11.2.10",
    "@angular/compiler": "~11.2.10",
    "@angular/core": "~11.2.10",
    "@angular/forms": "~11.2.10",
    "@angular/platform-browser": "~11.2.10",
    "@angular/platform-browser-dynamic": "~11.2.10",
    "@angular/router": "~11.2.10",
    "rxjs": "~6.6.0",
    "tslib": "^2.0.0",
    "zone.js": "~0.11.3"
  },
  "devDependencies": {
    "@angular-devkit/build-angular": "~0.1102.9",
    "@angular/cli": "~11.2.9",
    "@angular/compiler-cli": "~11.2.10",
    "@types/jasmine": "~3.6.0",
    "@types/node": "^12.11.1",
    "codelyzer": "^6.0.0",
    "jasmine-core": "~3.6.0",
    "jasmine-spec-reporter": "~5.0.0",
    "karma": "~6.1.0",
    "karma-chrome-launcher": "~3.1.0",
    "karma-coverage": "~2.0.3",
    "karma-jasmine": "~4.0.0",
    "karma-jasmine-html-reporter": "^1.5.0",
    "protractor": "~7.0.0",
    "ts-node": "~8.3.0",
    "tslint": "~6.1.0",
    "typescript": "~4.1.5"
  }
}

The package-lock.json here

Results

The node_modules folder contains 26982 * .js files:

$ find . -name '*.js' | wc -l
26982

Number of functions found: 338230

sqlite> select count(*) from info;
338230

Including unique: 130886

sqlite> Select count(*) from (SELECT hash, count(id) as c FROM info group By hash);
130886

Whence it follows that 130886/338230 * 100% = 39% of the functions are really unique, and the rest are duplicates of existing ones.

You can download the csv file for self-checking here.

Top 20 most popular functions in `node_modules` for an Angular project

Function with the largest number of duplicates.

SELECT hash, count(id) as c FROM info group By hash order by c desc LIMIT 20;

285d00ca29fcc46aa113c7aefc63827d, 2730 identical
```
const z=function(){};
```
cf6a0564f1128496d1e4706f302787d6, 1871 identical, function names usually: __export
```
function MORK(r){for(var o in r)exports.hasOwnProperty(o)||(exports[o]=r[o])}
```
12f746f2689073d5c949998e0216f68a, 1174 identical, function names_interopRequireDefault и __importDefault
```
function MORK(e){return e&&e.__esModule?e:{default:e}}
```
7d1e7aad635be0f7382696c4f846beae, 772 identical
```
function MORK(){}
```
c2da306af9b041ba213e3b189699d45c, 699 identical
```
const z=function(o,_){o.__proto__=_};
```
c41eb44114860f3aa1e9fa79c779e02f, 697 identical, functions name: __
```
function MORK(){this.constructor=d}
```

5911b29c89fa44f28ce030aa5e433327, 691 identical

const z=function(n,o){for(var r in o)o.hasOwnProperty(r)&&(n[r]=o[r])};

05c2b9b254be7e4b8460274c1353b5ad, 653 identical

const z=function(t,n){return extendStatics=Object.setPrototypeOf||{__proto__:[]}instanceof Array&&function(t,n){t.__proto__=n}||function(t,n){for(var o in n)n.hasOwnProperty(o)&&(t[o]=n[o])},extendStatics(t,n)};

fcaede1b9e574664c893e75ee7dc1d8b, 652 identical

const z=function(t,o){function e(){this.constructor=t}extendStatics(t,o),t.prototype=null===o?Object.create(o):(e.prototype=o.prototype,new e)};

e743dd760a03449be792c00e65154a48, 635 identical

function(){var r=function(t,o){return(r=Object.setPrototypeOf||{__proto__:[]}instanceof Array&&function(t,o){t.__proto__=o}||function(t,o){for(var n in o)o.hasOwnProperty(n)&&(t[n]=o[n])})(t,o)};return function(t,o){function n(){this.constructor=t}r(t,o),t.prototype=null===o?Object.create(o):(n.prototype=o.prototype,new n)}};

777c390d3cc4663f8ebe4933e5c33e9d, 441 identical, function names usually: Rule, AsapScheduler, ComplexOuterSubscriber и другие
```
function MORK(){return null!==_super&&_super.apply(this,arguments)||this}
```
27628ad740cff22386b0ff029e844e85, 385 identical, function names usually: identity, forwardResolution и тд
```
function MORK(n){return n}
```
f6822db5c8812f4b09ab142afe908cda, 375 identical
```
const z=function(n){};
```
d98a03a472615305b012eceb3e9947d5, 330 identical
```
const z=function(n,c){};
```
4728096fca2b3575800dafbdebf4276a, 324 identical
```
const z=function(n){return n};
```

7b769d3e4ba438fc53b42ad8bece86ba, 289 identical, function names:plural

function MORK(t){var r=Math.floor(Math.abs(t)),t=t.toString().replace(/^[^.]*\.?/,"").length;return 1===r&&0===t?1:5}

7d6f69751712ef9fa94238b38120adc6, 255 identical
```
const z=function(){return this};
```
b7081aad7510b0993fcb57bfb95c5c2c, 250 identical
```
const z=function(){return!1};
```
d665499155e104f749bf3a67caed576a, 250 identical
```
const z=function(n){return null==n};
```

99fa7dfce87269a564fc848a7f7515b9, 255 identical

const z=function(a,c){this._array.forEach(a,c)};

Files with the largest number of functions

SELECT count(id) as c, path FROM info group By path order by c desc LIMIT 20;

What about the production js bundle?

Nothing really interesting. The Webpack works efficiently. 95% functions are unique of the 1282 used. Here are top five functions that have duplicates:

What about React?

I also checked React. I put the comparison in the table below:

You can download the csv file for self-checking here.

Top 20 most popular functions in `node_modules` for the React project

The react project was generated by create-react-app my-app. The files package.json and yarn.lock are here.

12f746f2689073d5c949998e0216f68a, 1377 identical, function names usually: _interopRequireDefault
```
function MORK(e){return e&&e.__esModule?e:{default:e}}
```
285d00ca29fcc46aa113c7aefc63827d, 1243 identical
```
const z=function(){};
```
3f993321f73e83f277c20c178e5587b9, 989 identical
```
const z=function(){return data};
```
54782ec6cef850906484808b86946b33, 299 identical
```
const z=()=>{};
```
7d1e7aad635be0f7382696c4f846beae, 278 identical, function names: emptyFunction, Generator
```
function MORK(){}
```
d11004e998280b565ad084b0ad5ca214, 239 identical
```
const z=function(){return cache};
```

a02c66d8928b3353552e4804c6714326, 237 identical, function names: _getRequireWildcardCache

function MORK(){if("function"!=typeof WeakMap)return null;var e=new WeakMap;return _getRequireWildcardCache=function(){return e},e}

79e9bd3cdf15cf0af97f73ccaed50fa0, 231 identical, function names _interopRequireWildcard

function MORK(e){if(e&&e.__esModule)return e;if(null===e||"object"!=typeof e&&"function"!=typeof e)return{default:e};var t=_getRequireWildcardCache();if(t&&t.has(e))return t.get(e);var r,n,o={},c=Object.defineProperty&&Object.getOwnPropertyDescriptor;for(r in e)Object.prototype.hasOwnProperty.call(e,r)&&((n=c?Object.getOwnPropertyDescriptor(e,r):null)&&(n.get||n.set)?Object.defineProperty(o,r,n):o[r]=e[r]);return o.default=e,t&&t.set(e,o),o}

7d6f69751712ef9fa94238b38120adc6, 189 identical
```
const z=function(){return this};
```

b8dd34af96b042c23a4be7f82c881fe4, 176 identical

const z=function(n,o,c,i){n[i=void 0===i?c:i]=o[c]};

863a48e36413feba8bb299623dbc9b20, 174 identical

const z=function(e,n,t,o){void 0===o&&(o=t),Object.defineProperty(e,o,{enumerable:!0,get:function(){return n[t]}})};

2482d2afd404031c67adb9cbc012768b, 174 identical
```
const z=function(){return m[k]};
```
4728096fca2b3575800dafbdebf4276a, 170 identical
```
const z=function(n){return n};
```
bf8b05684375b26205e50fa27317057e, 157 identical
```
const z=s=>exposed.has(s);
```

fd114ee6b71ee06738b5b547b00e8102, 156 identical

const z=(r,e,p)=>{var t=makeWrapper(r);return exports.setup(t,r,e,p)};

df1c43e5a72e92d11bdefcead13a5e14, 156 identical

const z=t=>utils.isObject(t)&&t instanceof Impl.implementation;

094afc30995ff28993ec5326e8b3c4d4, 156 identical

const z=i=>utils.isObject(i)&&utils.hasOwn(i,implSymbol)&&i[implSymbol]instanceof Impl.implementation;

042490db7093660e74a762447f64f950, 156 identical

const z=(r,e,t)=>{t=exports.create(r,e,t);return utils.implForWrapper(t)};

5c5979ec3533f13b22153de05ffc64d5, 154 identical

const z=function(e){if(e&&e.__esModule)return e;var t={};if(null!=e)for(var r in e)"default"!==r&&Object.prototype.hasOwnProperty.call(e,r)&&__createBinding(t,e,r);return __setModuleDefault(t,e),t};

50645492c50621c0847c4ebd1fdd65cd, 154 identical

const z=function(e,n){Object.defineProperty(e,"default",{enumerable:!0,value:n})};

Which files use function 8 (79e9bd3cdf15cf0af97f73ccaed50fa0)

View file list

The list is long

/jest-worker/build/base/BaseWorkerPool.js
/@svgr/hast-util-to-babel-ast/lib/index.js
/@svgr/hast-util-to-babel-ast/lib/handlers.js
/@svgr/hast-util-to-babel-ast/lib/stringToObjectStyle.js
/@svgr/hast-util-to-babel-ast/lib/getAttributes.js
/babel-jest/node_modules/@babel/core/lib/transform-file.js
/babel-jest/node_modules/@babel/core/lib/config/files/configuration.js
/babel-jest/node_modules/@babel/core/lib/config/files/utils.js
/babel-jest/node_modules/@babel/core/lib/config/full.js
/babel-jest/node_modules/@babel/core/lib/transformation/normalize-file.js
/babel-jest/node_modules/@babel/core/lib/transformation/file/file.js
/babel-jest/node_modules/@babel/core/lib/tools/build-external-helpers.js
/babel-jest/node_modules/@babel/core/lib/index.js
/jest-pnp-resolver/node_modules/jest-resolve/build/defaultResolver.js
/jest-pnp-resolver/node_modules/jest-resolve/build/ModuleNotFoundError.js
/jest-circus/build/utils.js
/jest-haste-map/build/ModuleMap.js
/jest-haste-map/build/lib/normalizePathSep.js
/jest-haste-map/build/lib/fast_path.js
/jest-haste-map/build/lib/WatchmanWatcher.js
/jest-haste-map/build/worker.js
/jest-haste-map/build/getMockName.js
/jest-haste-map/build/HasteFS.js
/jest-haste-map/build/crawlers/watchman.js
/jest-jasmine2/build/index.js
/eslint/node_modules/@babel/code-frame/lib/index.js
/mini-css-extract-plugin/dist/index.js
/react-scripts/node_modules/@babel/core/lib/transform-file.js
/react-scripts/node_modules/@babel/core/lib/config/files/configuration.js
/react-scripts/node_modules/@babel/core/lib/config/files/utils.js
/react-scripts/node_modules/@babel/core/lib/config/full.js
/react-scripts/node_modules/@babel/core/lib/transformation/normalize-file.js
/react-scripts/node_modules/@babel/core/lib/transformation/file/file.js
/react-scripts/node_modules/@babel/core/lib/tools/build-external-helpers.js
/react-scripts/node_modules/@babel/core/lib/index.js
/react-scripts/node_modules/jest-resolve/build/defaultResolver.js
/react-scripts/node_modules/jest-resolve/build/ModuleNotFoundError.js
/eslint-plugin-flowtype/dist/utilities/index.js
/jest-util/build/index.js
/jest-util/build/createDirectory.js
/jest-util/build/installCommonGlobals.js
/babel-preset-react-app/node_modules/@babel/plugin-transform-react-jsx-development/node_modules/@babel/core/lib/transform-file.js
/babel-preset-react-app/node_modules/@babel/plugin-transform-react-jsx-development/node_modules/@babel/core/lib/config/files/configuration.js
/babel-preset-react-app/node_modules/@babel/plugin-transform-react-jsx-development/node_modules/@babel/core/lib/config/files/utils.js
/babel-preset-react-app/node_modules/@babel/plugin-transform-react-jsx-development/node_modules/@babel/core/lib/config/full.js
/babel-preset-react-app/node_modules/@babel/plugin-transform-react-jsx-development/node_modules/@babel/core/lib/transformation/normalize-file.js
/babel-preset-react-app/node_modules/@babel/plugin-transform-react-jsx-development/node_modules/@babel/core/lib/transformation/file/file.js
/babel-preset-react-app/node_modules/@babel/plugin-transform-react-jsx-development/node_modules/@babel/core/lib/tools/build-external-helpers.js
/babel-preset-react-app/node_modules/@babel/plugin-transform-react-jsx-development/node_modules/@babel/core/lib/index.js
/babel-preset-react-app/node_modules/@babel/plugin-transform-react-pure-annotations/node_modules/@babel/core/lib/transform-file.js
/babel-preset-react-app/node_modules/@babel/plugin-transform-react-pure-annotations/node_modules/@babel/core/lib/config/files/configuration.js
/babel-preset-react-app/node_modules/@babel/plugin-transform-react-pure-annotations/node_modules/@babel/core/lib/config/files/utils.js
/babel-preset-react-app/node_modules/@babel/plugin-transform-react-pure-annotations/node_modules/@babel/core/lib/config/full.js
/babel-preset-react-app/node_modules/@babel/plugin-transform-react-pure-annotations/node_modules/@babel/core/lib/transformation/normalize-file.js
/babel-preset-react-app/node_modules/@babel/plugin-transform-react-pure-annotations/node_modules/@babel/core/lib/transformation/file/file.js
/babel-preset-react-app/node_modules/@babel/plugin-transform-react-pure-annotations/node_modules/@babel/core/lib/tools/build-external-helpers.js
/babel-preset-react-app/node_modules/@babel/plugin-transform-react-pure-annotations/node_modules/@babel/core/lib/index.js
/babel-preset-react-app/node_modules/@babel/plugin-transform-react-jsx/node_modules/@babel/core/lib/transform-file.js
/babel-preset-react-app/node_modules/@babel/plugin-transform-react-jsx/node_modules/@babel/core/lib/config/files/configuration.js
/babel-preset-react-app/node_modules/@babel/plugin-transform-react-jsx/node_modules/@babel/core/lib/config/files/utils.js
/babel-preset-react-app/node_modules/@babel/plugin-transform-react-jsx/node_modules/@babel/core/lib/config/full.js
/babel-preset-react-app/node_modules/@babel/plugin-transform-react-jsx/node_modules/@babel/core/lib/transformation/normalize-file.js
/babel-preset-react-app/node_modules/@babel/plugin-transform-react-jsx/node_modules/@babel/core/lib/transformation/file/file.js
/babel-preset-react-app/node_modules/@babel/plugin-transform-react-jsx/node_modules/@babel/core/lib/tools/build-external-helpers.js
/babel-preset-react-app/node_modules/@babel/plugin-transform-react-jsx/node_modules/@babel/core/lib/index.js
/babel-preset-react-app/node_modules/@babel/preset-env/node_modules/@babel/plugin-proposal-class-properties/node_modules/@babel/core/lib/transform-file.js
/babel-preset-react-app/node_modules/@babel/preset-env/node_modules/@babel/plugin-proposal-class-properties/node_modules/@babel/core/lib/config/files/configuration.js
/babel-preset-react-app/node_modules/@babel/preset-env/node_modules/@babel/plugin-proposal-class-properties/node_modules/@babel/core/lib/config/files/utils.js
/babel-preset-react-app/node_modules/@babel/preset-env/node_modules/@babel/plugin-proposal-class-properties/node_modules/@babel/core/lib/config/full.js
/babel-preset-react-app/node_modules/@babel/preset-env/node_modules/@babel/plugin-proposal-class-properties/node_modules/@babel/core/lib/transformation/normalize-file.js
/babel-preset-react-app/node_modules/@babel/preset-env/node_modules/@babel/plugin-proposal-class-properties/node_modules/@babel/core/lib/transformation/file/file.js
/babel-preset-react-app/node_modules/@babel/preset-env/node_modules/@babel/plugin-proposal-class-properties/node_modules/@babel/core/lib/tools/build-external-helpers.js
/babel-preset-react-app/node_modules/@babel/preset-env/node_modules/@babel/plugin-proposal-class-properties/node_modules/@babel/core/lib/index.js
/babel-preset-react-app/node_modules/@babel/preset-env/node_modules/@babel/plugin-proposal-optional-chaining/node_modules/@babel/core/lib/transform-file.js
/babel-preset-react-app/node_modules/@babel/preset-env/node_modules/@babel/plugin-proposal-optional-chaining/node_modules/@babel/core/lib/config/files/configuration.js
/babel-preset-react-app/node_modules/@babel/preset-env/node_modules/@babel/plugin-proposal-optional-chaining/node_modules/@babel/core/lib/config/files/utils.js
/babel-preset-react-app/node_modules/@babel/preset-env/node_modules/@babel/plugin-proposal-optional-chaining/node_modules/@babel/core/lib/config/full.js
/babel-preset-react-app/node_modules/@babel/preset-env/node_modules/@babel/plugin-proposal-optional-chaining/node_modules/@babel/core/lib/transformation/normalize-file.js
/babel-preset-react-app/node_modules/@babel/preset-env/node_modules/@babel/plugin-proposal-optional-chaining/node_modules/@babel/core/lib/transformation/file/file.js
/babel-preset-react-app/node_modules/@babel/preset-env/node_modules/@babel/plugin-proposal-optional-chaining/node_modules/@babel/core/lib/tools/build-external-helpers.js
/babel-preset-react-app/node_modules/@babel/preset-env/node_modules/@babel/plugin-proposal-optional-chaining/node_modules/@babel/core/lib/index.js
/babel-preset-react-app/node_modules/@babel/preset-env/node_modules/@babel/plugin-proposal-nullish-coalescing-operator/node_modules/@babel/core/lib/transform-file.js
/babel-preset-react-app/node_modules/@babel/preset-env/node_modules/@babel/plugin-proposal-nullish-coalescing-operator/node_modules/@babel/core/lib/config/files/configuration.js
/babel-preset-react-app/node_modules/@babel/preset-env/node_modules/@babel/plugin-proposal-nullish-coalescing-operator/node_modules/@babel/core/lib/config/files/utils.js
/babel-preset-react-app/node_modules/@babel/preset-env/node_modules/@babel/plugin-proposal-nullish-coalescing-operator/node_modules/@babel/core/lib/config/full.js
/babel-preset-react-app/node_modules/@babel/preset-env/node_modules/@babel/plugin-proposal-nullish-coalescing-operator/node_modules/@babel/core/lib/transformation/normalize-file.js
/babel-preset-react-app/node_modules/@babel/preset-env/node_modules/@babel/plugin-proposal-nullish-coalescing-operator/node_modules/@babel/core/lib/transformation/file/file.js
/babel-preset-react-app/node_modules/@babel/preset-env/node_modules/@babel/plugin-proposal-nullish-coalescing-operator/node_modules/@babel/core/lib/tools/build-external-helpers.js
/babel-preset-react-app/node_modules/@babel/preset-env/node_modules/@babel/plugin-proposal-nullish-coalescing-operator/node_modules/@babel/core/lib/index.js
/babel-preset-react-app/node_modules/@babel/preset-env/node_modules/@babel/plugin-proposal-numeric-separator/node_modules/@babel/core/lib/transform-file.js
/babel-preset-react-app/node_modules/@babel/preset-env/node_modules/@babel/plugin-proposal-numeric-separator/node_modules/@babel/core/lib/config/files/configuration.js
/babel-preset-react-app/node_modules/@babel/preset-env/node_modules/@babel/plugin-proposal-numeric-separator/node_modules/@babel/core/lib/config/files/utils.js
/babel-preset-react-app/node_modules/@babel/preset-env/node_modules/@babel/plugin-proposal-numeric-separator/node_modules/@babel/core/lib/config/full.js
/babel-preset-react-app/node_modules/@babel/preset-env/node_modules/@babel/plugin-proposal-numeric-separator/node_modules/@babel/core/lib/transformation/normalize-file.js
/babel-preset-react-app/node_modules/@babel/preset-env/node_modules/@babel/plugin-proposal-numeric-separator/node_modules/@babel/core/lib/transformation/file/file.js
/babel-preset-react-app/node_modules/@babel/preset-env/node_modules/@babel/plugin-proposal-numeric-separator/node_modules/@babel/core/lib/tools/build-external-helpers.js
/babel-preset-react-app/node_modules/@babel/preset-env/node_modules/@babel/plugin-proposal-numeric-separator/node_modules/@babel/core/lib/index.js
/babel-preset-react-app/node_modules/@babel/preset-env/lib/targets-parser.js
/babel-preset-react-app/node_modules/@babel/preset-env/lib/index.js
/babel-preset-react-app/node_modules/@babel/preset-env/lib/utils.js
/babel-preset-react-app/node_modules/@babel/preset-react/node_modules/@babel/plugin-transform-react-display-name/node_modules/@babel/core/lib/transform-file.js
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/babel-preset-react-app/node_modules/@babel/preset-react/node_modules/@babel/plugin-transform-react-display-name/node_modules/@babel/core/lib/config/files/utils.js
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Сonclusions?

Perhaps this little research will give someone thoughts about refactoring. Or changing the programming approach.

It is good that people use some common approaches and patterns for programming.

It's bad that there is a lot of copy-paste.

P.S.

Used scripts can be found on GitHub