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https://github.com/vberlier/extract-math
Extract TeX math environments.
https://github.com/vberlier/extract-math
katex latex math tex
Last synced: 3 months ago
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Extract TeX math environments.
- Host: GitHub
- URL: https://github.com/vberlier/extract-math
- Owner: vberlier
- License: mit
- Created: 2019-03-22T14:56:07.000Z (almost 6 years ago)
- Default Branch: master
- Last Pushed: 2023-03-04T03:26:48.000Z (almost 2 years ago)
- Last Synced: 2024-10-02T08:34:30.267Z (3 months ago)
- Topics: katex, latex, math, tex
- Language: TypeScript
- Size: 2.48 MB
- Stars: 9
- Watchers: 3
- Forks: 2
- Open Issues: 8
-
Metadata Files:
- Readme: README.md
- Funding: .github/FUNDING.yml
- License: LICENSE
Awesome Lists containing this project
README
# extract-math
[](https://travis-ci.com/vberlier/extract-math)
[](https://www.npmjs.com/package/extract-math)
[](https://bundlephobia.com/result?p=extract-math)
> Extract TeX math environments.
This package parses [TeX shorthands](https://en.wikibooks.org/wiki/LaTeX/Mathematics#Mathematics_environments) for mathematics environments and extracts inline formulas (e.g.: `$x + 1$`) and displayed equations (e.g.: `$$\sum_{i=1}^n 2^i$$`).
```js
import { extractMath } from 'extract-math'
const segments = extractMath('hello $e^{i\\pi}$')
console.log(segments)
// Output: [
// { type: 'text', math: false, value: 'hello ', raw: 'hello ' },
// { type: 'inline', math: true, value: 'e^{i\\pi}', raw: 'e^{i\\pi}' }
// ]
```
The primary use-case is to process the math segments with a math typesetting library like [KaTeX](https://katex.org/).
## Installation
You can install `extract-math` with your `npm` client of choice.
```bash
$ npm install extract-math
```
## Usage
### extractMath(input, options?)
Parse the input string and return an array of `Segment` objects. `Segment` objects are defined by the following typescript interface:
```ts
interface Segment {
type: 'text' | 'display' | 'inline'
math: boolean
value: string
raw: string
}
```
> The `Segment` interface can be imported with `import { Segment } from 'extract-math'`
The function splits the input string into 3 different types of segments:
- Plain text segments have a `text` type and the `math` property set to `false`
- Displayed equations have a `display` type and the `math` property set to `true`
- Inline formulas have an `inline` type and the `math` property set to `true`
The function will check that the closing delimiter isn't immediately followed by a digit before extracting a math segment. This prevents input like `$20,000 and $30,000` from being interpreted as inline math.
The second parameter is optional and lets you specify custom options:
```ts
interface ExtractMathOptions {
escape?: string
delimiters?: {
inline?: [string, string]
display?: [string, string]
}
allowSurroundingSpace?: Array<'display' | 'inline'>
}
```
> The `ExtractMathOptions` interface can be imported with `import { ExtractMathOptions } from 'extract-math'`
Here are the default values:
```js
{
escape: '\\',
delimiters: {
inline: ['$', '$'],
display: ['$$', '$$']
},
allowSurroundingSpace: ['display']
}
```
You can extract formulas that use LaTeX math delimiters with the following options:
```js
const segments = extractMath('hello \\(e^{i\\pi}\\)', {
delimiters: {
inline: ['\\(', '\\)'],
display: ['\\[', '\\]']
}
})
console.log(segments)
// Output: [
// { type: 'text', math: false, value: 'hello ', raw: 'hello ' },
// { type: 'inline', math: true, value: 'e^{i\\pi}', raw: 'e^{i\\pi}' }
// ]
```
By default, only the `display` mode allows the formula to be surrounded by space. You can change this with the `allowSurroundingSpace` option:
```js
segments = extractMath('$ 42 $$$ 42 $$', {
allowSurroundingSpace: ['inline', 'display']
})
console.log(segments)
// Output: [
// { type: 'inline', math: true, value: ' 42 ', raw: ' 42 ' },
// { type: 'display', math: true, value: ' 42 ', raw: ' 42 ' }
// ]
```
### Escaping
Any delimiter immediately preceded by a backslash `\` will be automatically escaped.
```js
const segments = extractMath('in plain \\$ text $$in \\$ equation$$')
console.log(segments)
// Output: [
// { type: 'text', math: false, value: 'in plain $ text ', raw: 'in plain $ text ' },
// { type: 'display', math: true, value: 'in $ equation', raw: 'in \\$ equation' }
// ]
```
The `raw` property is set to the original string without interpreting the escape sequences. For plain text segments, the property is equal to the `value` property.
This comes in handy if you're feeding the math expressions to a math typesetting library like [KaTeX](https://katex.org/) that expects dollar signs to be escaped.
```js
katex.render(segments[1].raw, ...)
```
## Contributing
Contributions are welcome. This project uses [jest](https://jestjs.io/) for testing.
```bash
$ npm test
```
The code follows the [javascript standard](https://standardjs.com/) style guide [adapted for typescript](https://github.com/standard/eslint-config-standard-with-typescript).
```bash
$ npm run lint
```
---
License - [MIT](https://github.com/vberlier/extract-math/blob/master/LICENSE)