README.md•2.83 kB
# jest-docblock
`jest-docblock` is a package that can extract and parse a specially-formatted comment called a "docblock" at the top of a file.
A docblock looks like this:
```js
/**
* Stuff goes here!
*/
```
Docblocks can contain pragmas, which are words prefixed by `@`:
```js
/**
* Pragma incoming!
*
* @flow
*/
```
Pragmas can also take arguments:
```js
/**
* Check this out:
*
* @myPragma it is so cool
*/
```
`jest-docblock` can:
- extract the docblock from some code as a string
- parse a docblock string's pragmas into an object
- print an object and some comments back to a string
## Installation
```sh
# with yarn
$ yarn add jest-docblock
# with npm
$ npm install jest-docblock
```
## Usage
```js
const code = `
/**
* Everything is awesome!
*
* @everything is:awesome
* @flow
*/
export const everything = Object.create(null);
export default function isAwesome(something) {
return something === everything;
}
`;
const {
extract,
strip,
parse,
parseWithComments,
print,
} = require('jest-docblock');
const docblock = extract(code);
console.log(docblock); // "/**\n * Everything is awesome!\n * \n * @everything is:awesome\n * @flow\n */"
const stripped = strip(code);
console.log(stripped); // "export const everything = Object.create(null);\n export default function isAwesome(something) {\n return something === everything;\n }"
const pragmas = parse(docblock);
console.log(pragmas); // { everything: "is:awesome", flow: "" }
const parsed = parseWithComments(docblock);
console.log(parsed); // { comments: "Everything is awesome!", pragmas: { everything: "is:awesome", flow: "" } }
console.log(print({pragmas, comments: 'hi!'})); // /**\n * hi!\n *\n * @everything is:awesome\n * @flow\n */;
```
## API Documentation
### `extract(contents: string): string`
Extracts a docblock from some file contents. Returns the docblock contained in `contents`. If `contents` did not contain a docblock, it will return the empty string (`""`).
### `strip(contents: string): string`
Strips the top docblock from a file and return the result. If a file does not have a docblock at the top, then return the file unchanged.
### `parse(docblock: string): {[key: string]: string | string[] }`
Parses the pragmas in a docblock string into an object whose keys are the pragma tags and whose values are the arguments to those pragmas.
### `parseWithComments(docblock: string): { comments: string, pragmas: {[key: string]: string | string[]} }`
Similar to `parse` except this method also returns the comments from the docblock. Useful when used with `print()`.
### `print({ comments?: string, pragmas?: {[key: string]: string | string[]} }): string`
Prints an object of key-value pairs back into a docblock. If `comments` are provided, they will be positioned on the top of the docblock.