README.md
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# remove cstyle comments (rm-cstyle-cmts)
remove c style comments from text file. (javascript source, json file etc)
* This module removes comments from source files such as `typescript` and `javascript`.
It does not remove lines that are meaningful to `typescript`, such as `@ts-ignore` and `<reference types="node"/>`,
but removes other **single line comments** and **multi line comments**.
* For other **single line comment** and **multi line comment**, it is possible to control which comment is removed by setting [**scan listener**](#the-walkthrough-mode).
* This module is [much faster than the popular comment removal module](#performance-measurement-with-benchmarkjs).
* [**gulp plugin**](#rm-cstyle-cmts-gulp-plugin) is available.
* [**web version**](#rm-cstyle-cmts-web-version) is available.
* new property `keepJsDoc` (v3.3.11)
* regex flags strict check (v3.3.15)
+ Even if it is not written as a regular expression in the text,
it will be detected if it is valid as a regex (this is by design).
## install
* npm
```shell
$ npm install rm-cstyle-cmts --save-dev
# shorthand
$ npm i rm-cstyle-cmts -D
```
* yarn
```shell
$ yarn add rm-cstyle-cmts -D
```
## Features
+ remove mode
```js
const rmc = require("rm-cstyle-cmts");
const removed = rmc("<source file content>");
```
+ walkthrough mode (walkthrough mode does things like statistics for source code comments by setting a scan listener.)
```js
const rmc = require("rm-cstyle-cmts");
/** @type {Map<string, number>} */
const tagStatistics = new Map();
/**
* Take statistics for jsDoc tag
*
* @param {object} context
* @param {TScannerEventContext["event"]} context.event - currently EScannerEvent.(SingleLineComment | MultiLineComment) only
* @param {TScannerEventContext["fragment"]} context.fragment comment body
* @param {TScannerEventContext["offset"]} context.offset - fragment start offset from original source
*/
function handleScanEvent({ event, fragment, offset }) => {
if (event === /*EScannerEvent.MultiLineComment*/1) {
if (/^\/\*\*[^*]/.test(fragment)) {
const re = /(?<=[\s\*{])@\w+(?=\s)/g;
/** @type {RegExpExecArray} */
let m;
while (m = re.exec(fragment)) {
const tag = m[0];
let count = tagStatistics.get(tag) || 0;
tagStatistics.set(tag, count + 1);
}
}
}
return true;
}
// At current implementation, accept one listener only
rmc.setListener(handleScanEvent);
rmc.walk("<source file content>");
```
## API
node module.
```js
const rmc = require("rm-cstyle-cmts");
```
### run as remove mode
```js
const opt = { collectRegex: true, showErrorMessage: true, preserveBlanks: true };
const removed = rmc("<source file content>", opt);
```
- **source** `{string}` -- The target source content.
- **opt** `{object}`
- [**opt.collectRegex**](https://github.com/jeffy-g/rm-cstyle-cmts/blob/master/src/index.d.ts#L19) `{true | undefined}` -- Whether collect detected regex. Default: `undefined`.
- [**opt.showErrorMessage**](https://github.com/jeffy-g/rm-cstyle-cmts/blob/master/src/index.d.ts#L27) `{true | undefined}` -- Whether to display an error message. Default: `undefined`.
- [**opt.preserveBlanks**](https://github.com/jeffy-g/rm-cstyle-cmts/blob/master/src/index.d.ts#L37) `{true | undefined}` -- Whether preserve whitespace and blank lines. Default: `undefined`.
### run as walkthrough mode
```js
const opt = { collectRegex: true, showErrorMessage: true };
rmc.walk("<source file content>", opt);
```
- **source** `{string}` -- The target source content.
- **opt** `{object}`
- [**opt.collectRegex**](https://github.com/jeffy-g/rm-cstyle-cmts/blob/master/src/index.d.ts#L19) `{true | undefined}` -- Whether collect detected regex. Default: `undefined`.
- [**opt.showErrorMessage**](https://github.com/jeffy-g/rm-cstyle-cmts/blob/master/src/index.d.ts#L27) `{true | undefined}` -- Whether to display an error message. Default: `undefined`.
## Playground
+ [rm-cstyle-cmts Playground (powered by monaco-editor)](https://rm-cstyle-cmts-playground.netlify.com/)
## Performance measurement with `Benchmark.js`
```shell
$ npm run benchmark
```
+ We are comparing the process of deleting only `comment` from the following sample
<details>
```js
const json = `// see: http://json.schemastore.org/tsconfig
{
"compilerOptions": {
/* Basic Options */
"target": "es5", /* Specify ECMAScript target version: 'ES3' (default), 'ES5', 'ES2015', 'ES2016', 'ES2017', 'ES2018', 'ES2019' or 'ESNEXT'. */
"module": "commonjs", /* Specify module code generation: 'none', 'commonjs', 'amd', 'system', 'umd', 'es2015', or 'ESNext'. */
// "allowJs": true, /* Allow javascript files to be compiled. */
// "checkJs": true, /* Report errors in .js files. */
// "declaration": true, /* Generates corresponding '.d.ts' file. */
// "sourceMap": true, /* Generates corresponding '.map' file. */
// "outFile": "./", /* Concatenate and emit output to single file. */
// "outDir": "./", /* Redirect output structure to the directory. */
/* Strict Type-Checking Options */
"strict": true, /* Enable all strict type-checking options. */
// "strictNullChecks": true, /* Enable strict null checks. */
// "strictFunctionTypes": true, /* Enable strict checking of function types. */
/* Additional Checks */
// "noUnusedLocals": true, /* Report errors on unused locals. */
// "noUnusedParameters": true, /* Report errors on unused parameters. */
/* Module Resolution Options */
// "baseUrl": "./", /* Base directory to resolve non-absolute module names. */
// "typeRoots": [], /* List of folders to include type definitions from. */
"esModuleInterop": true /* Enables emit interoperability between CommonJS and ES Modules via creation of namespace objects for all imports. Implies 'allowSyntheticDefaultImports'. */
/* Experimental Options */
// "experimentalDecorators": true, /* Enables experimental support for ES7 decorators. */
// "emitDecoratorMetadata": true, /* Enables experimental support for emitting type metadata for decorators. */
},
"files": [
"y"
]
}`;
```
</details>
> ### node v15.8.0
```shell
$ yarn benchmark
yarn run v1.22.18
$ cd etc/bench && yarn install && yarn start
[1/4] Resolving packages...
success Already up-to-date.
$ node bench.mjs
- - - - - - - bench mark test - - - - - - - - -
Platform info:
Windows_NT 10.0.19045 x64
Node.JS: 15.8.0
V8 : 8.6.395.17-node.23
Intel(R) Core(TM) i7-3770 CPU @ 3.40GHz x 8
strip-comments x 11,184 ops/sec ±0.69% (84 runs sampled)
strip-json-comments x 17,525 ops/sec ±0.86% (94 runs sampled)
rm-cstyle-cmts x 168,734 ops/sec ±0.84% (92 runs sampled)
rm-cstyle-cmts (webpack) x 165,568 ops/sec ±1.22% (94 runs sampled)
rm-cstyle-cmts (umd) x 164,756 ops/sec ±0.74% (94 runs sampled)
- - done - -
all results are equals? true # see NOTE:
Done in 28.22s.
```
> ### node 22.12.0
```shell
yarn run v1.22.18
$ cd etc/bench && yarn install && yarn start
[1/4] Resolving packages...
[2/4] Fetching packages...
[3/4] Linking dependencies...
[4/4] Building fresh packages...
$ node bench.mjs
- - - - - - - bench mark test - - - - - - - - -
Platform info:
Windows_NT 10.0.19045 x64
Node.JS: 22.12.0
V8 : 12.4.254.21-node.21
Intel(R) Core(TM) i7-3770 CPU @ 3.40GHz x 8
strip-comments x 12,301 ops/sec ±0.43% (94 runs sampled)
strip-json-comments x 17,116 ops/sec ±0.16% (95 runs sampled)
rm-cstyle-cmts x 218,466 ops/sec ±0.31% (96 runs sampled)
rm-cstyle-cmts (webpack) x 216,343 ops/sec ±0.74% (95 runs sampled)
rm-cstyle-cmts (umd) x 216,291 ops/sec ±0.28% (96 runs sampled)
- - done - -
all results are equals? true # see NOTE:
Done in 28.56s.
```
+ NOTE: `strip-comments` may be buggy and is excluded from comparison
## The `Walkthrough mode`
`Walkthrough mode` does not modify original source.
The current implementation calls the `listener` on __line comment__ and __multi-line comment__ scan events.
```ts
import * as rmc from "rm-cstyle-cmts";
/**
* @param {object} context
* @param {TScannerEventContext["event"]} context.event - currently EScannerEvent.(SingleLineComment | MultiLineComment) only
* @param {TScannerEventContext["fragment"]} context.fragment comment body
* @param {TScannerEventContext["offset"]} context.offset - fragment start offset from original source
*/
function handleScanEvent({ event, fragment, offset }) => {
if (event === /*EScannerEvent.MultiLineComment*/1) {
// remove mode: preserve JSDoc comment
// walkthrough mode: whether proceed walkthrough
return /^\/\*\*[^*]/.test(fragment);
}
return false;
}
// At current implementation, accept one listener only
rmc.setListener(handleScanEvent);
const opt = { collectRegex: true, showErrorMessage: true };
rmc("<commented source>", opt);
rmc.walk("<commented source>", opt);
```
> __NOTE__: Handling of listener in `remove mode` and `walkthrough mode`
+ In `walkthrough mode`: Returns `true` to continue processing. otherwise stop processing.
+ In `remove mode`: it returns `true` to preserve in the **line comment** and **multi line comment** deletion process.
## `rm-cstyle-cmts` gulp plugin
### gulp plugin sample task
+ sample task to scan javascript related files directly under `node_modules`
```shell
$ npm run grmc-test:cjs
```
### API of gulp plugin
```js
const gulp = require("gulp");
const grmc = require("rm-cstyle-cmts/cjs/gulp/");
const grmcOpt = {
preserveBlanks: undefined, // remove blank lines and trailing whitespace
renderProgress: true, // show progress
// isWalk: true // want walk through?
};
gulp.src(["./src/**/*.{js,jsx,ts,tsx}"]).pipe(
grmc.getTransformer(grmcOpt)
).pipe(gulp.dest("./tmp"));
```
#### gulp plugin options
- [**preserveBlanks**](https://github.com/jeffy-g/rm-cstyle-cmts/blob/9f110983eac55d29ff34e86ca366de450810cde1/src/gulp/index.d.ts#L32) `{true | undefined}` -- Whether preserve whitespace and blank lines. Default: `undefined`.
- [**renderProgress**](https://github.com/jeffy-g/rm-cstyle-cmts/blob/9f110983eac55d29ff34e86ca366de450810cde1/src/gulp/index.d.ts#L40) `{true | undefined}` -- log scan source path(relative) currently being processed. Default: `undefined`.
- [**collectRegex**](https://github.com/jeffy-g/rm-cstyle-cmts/blob/9f110983eac55d29ff34e86ca366de450810cde1/src/gulp/index.d.ts#L44) `{true | undefined}` -- Whether collect detected regex. Default: `undefined`.
- [**isWalk**](https://github.com/jeffy-g/rm-cstyle-cmts/blob/9f110983eac55d29ff34e86ca366de450810cde1/src/gulp/index.d.ts#L50) `{true | undefined}` -- Whether to run in walkthrough mode. Default: `undefined`.
- [**extraExtensions**](https://github.com/jeffy-g/rm-cstyle-cmts/blob/9f110983eac55d29ff34e86ca366de450810cde1/src/gulp/index.d.ts#L56) `{string[] | undefined}` -- Add additional extensions. Default: `undefined`.
- [**disableDefaultExtensions**](https://github.com/jeffy-g/rm-cstyle-cmts/blob/9f110983eac55d29ff34e86ca366de450810cde1/src/gulp/index.d.ts#L72) `{true | undefined}` -- use `extraExtensions` only, instead of `defaultExtensions`. Default: `undefined`.
+ `defaultExtensions` - ".js", ".jsx", ".ts", ".tsx", ".cjs", ".mjs", ".cts", ".mts"
- [**timeMeasure**](https://github.com/jeffy-g/rm-cstyle-cmts/blob/9f110983eac55d29ff34e86ca366de450810cde1/src/gulp/index.d.ts#L78) `{true | undefined}` -- Whether to record the processing time for each file (replace mode only). Default: `undefined`.
#### example with `scan listener`
```js
const gulp = require("gulp");
const grmc = require("rm-cstyle-cmts/cjs/gulp/");
// set scan event listener
grmc.getRmcInterface().setListener(({ event, fragment, offset }) => {
if (event === /*EScannerEvent.MultiLineComment*/1) {
// true: Concatenate fragment to result in "remove mode", continue walkthrough in "walkthrough mode".
// false: remove fragment in "remove mode", stop walkthrough in "walkthrough mode".
return /^\/\*(\*|!)\s/.test(fragment);
}
else if (event === /*EScannerEvent.SingleLineComment*/0) {
return /(?:\/\/\/?\s+@ts-\w+|\/\/\/\s*<reference)/.test(fragment);
}
// remove fragment in "remove mode", stop walkthrough in "walkthrough mode".
return false;
});
gulp.src(["./src/**/*.{js,jsx,ts,tsx}"]).pipe(
/**
* preserveBlanks : keep blank line and whitespaces, default is `undefined`.
*/
grmc.getTransformer({
preserveBlanks: undefined, // remove blank lines and trailing whitespace
renderProgress: true, // show progress
// isWalk: true // want walk through?
})
).pipe(gulp.dest("./tmp"));
```
## rm-cstyle-cmts web version
+ You can use web version from cdn such as `jsdelivr`.
+ can use the API through the `Rmc` global variable.
```html
<!-- or https://cdn.jsdelivr.net/npm/rm-cstyle-cmts@latest/umd/index.min.js -->
<script src="https://cdn.jsdelivr.net/npm/rm-cstyle-cmts@3/umd/index.min.js"></script>
```
```js
const source = `
/// <reference types="node"/>
import React from "react";
import ReactDOM from "react-dom";
/**
* jsdoc comment
*/
function App() {
return (
// TODO: can optionally include quote string in react syntax.
// such source input does not complete successfully.
<h1>Hello's world's</h1>
);
}
ReactDOM.render(<App />, document.getElementById("root"));
`;
/**
* You can use the API through the `Rmc` global variable.
*/
console.log(Rmc(source));
// print detected regex literals detail (in this case, nothing any result)
console.log(Rmc.getDetectedReContext());
// reset of related statistics
Rmc.reset();
```
## usage
> #### Case: single line input (js)
```js
const rmc = require("rm-cstyle-cmts");
const input = " /** block comment */ const a = \"this is apple! \\n\", b = 'quoted \"strings\"', \
c = `list:\\n1. \${a}\\n2. \${b}\\n\${ /* comments */ ` - len: \${a.length + b.length}`}\\n ---`; \
/* . */ let i = 2, n = 12 / 4 * 7/i; // last coment. !";
const result = rmc(input);
console.log(result);
//> const a = "this is apple! \n", b = 'quoted "strings"', c = `list:\n1. ${a}\n2. ${b}\n${ /* comments */ ` - len: ${a.length + b.length}`}\n ---`; let i = 2, n = 12 / 4 * 7/i;
```
> #### Case: json source
```js
const rmc = require("rm-cstyle-cmts");
const json = `// see: http://json.schemastore.org/tsconfig
{
"compilerOptions": {
/* Basic Options */
"target": "es5", /* Specify ECMAScript target version: 'ES3' (default), 'ES5', 'ES2015', 'ES2016', 'ES2017', 'ES2018', 'ES2019' or 'ESNEXT'. */
"module": "commonjs", /* Specify module code generation: 'none', 'commonjs', 'amd', 'system', 'umd', 'es2015', or 'ESNext'. */
// "allowJs": true, /* Allow javascript files to be compiled. */
// "checkJs": true, /* Report errors in .js files. */
// "declaration": true, /* Generates corresponding '.d.ts' file. */
// "sourceMap": true, /* Generates corresponding '.map' file. */
// "outFile": "./", /* Concatenate and emit output to single file. */
// "outDir": "./", /* Redirect output structure to the directory. */
/* Strict Type-Checking Options */
"strict": true, /* Enable all strict type-checking options. */
// "strictNullChecks": true, /* Enable strict null checks. */
// "strictFunctionTypes": true, /* Enable strict checking of function types. */
/* Additional Checks */
// "noUnusedLocals": true, /* Report errors on unused locals. */
// "noUnusedParameters": true, /* Report errors on unused parameters. */
/* Module Resolution Options */
// "baseUrl": "./", /* Base directory to resolve non-absolute module names. */
// "typeRoots": [], /* List of folders to include type definitions from. */
"esModuleInterop": true /* Enables emit interoperability between CommonJS and ES Modules via creation of namespace objects for all imports. Implies 'allowSyntheticDefaultImports'. */
/* Experimental Options */
// "experimentalDecorators": true, /* Enables experimental support for ES7 decorators. */
// "emitDecoratorMetadata": true, /* Enables experimental support for emitting type metadata for decorators. */
},
"files": [
"y"
]
}`;
const result = rmc(input);
console.log(result);
//> {
//> "compilerOptions": {
//> "target": "es5",
//> "module": "commonjs",
//> "strict": true,
//> "esModuleInterop": true
//> },
//> "files": [
//> "y"
//> ]
//> }
```