mdast-excerpt

!Build Status

mdast-excerpt allows you to get an excerpt from a markdown post. The code is
"borrowed" from gatsby-transformer-remark, which makes it possible to use excerpt
generation in other contexts outside of GatsbyJS. If you
want to know how the result looks like, check
Using Excerpts at GatsbyJS.

Input is a full markdown AST, output a pruned AST with the desired excerpt length and
intact markup.

This plugin becomes useful if the excerpt would stop in the middle of marked up text:

> This is a bold text -> This is a \\bold te...

when truncated by string length. With mdast-excerpt, then markup is truncated
correctly:

> This is a bold text -> This is a bold te...

My personal favourite is using mdast-excerpt in combination with
react-markdown (see futher below for
usage).

Install

``sh
npm install mdast-excerpt
`

Use

`js
const remark = require("remark")
const html = require("remark-html")
const excerptAst = require("mdast-excerpt")

// fake the plugin
const asExcerpt = options => node => excerptAst(node, options || {})

const input = "abc abc def ghi"
remark()
.use(asExcerpt, { omission: " Read More", pruneLength: 14 })
.use(html)
.processSync(input)
`

$3

You can use the astPlugins prop to supply the excerptAst transformer:

`jsx
import React from "react"
import ReactDOM from "react-dom"

import ReactMarkdown from "react-markdown"
import excerptAst from "mdast-excerpt"

const MarkdownExcerpt = ({ source, pruneLength = 14 }) => (
source={source}
astPlugins={[ast => excerptAst(ast, { pruneLength })]}
/>
)

const App = () => {
const input = "abc abc def ghi"
return
}

React.ReactDOM.render(, document.getElementById("root"))
`

API

You can call excerptAst as follows:

excerptAst(tree, { pruneLength: 1, truncate: false, omission:…})

The options are

- pruneLength: max length of the excerpt (default 140)
- truncate: truncate on exact length (true) or stop at whole words (default false)
- excerptSeparator: supply an excerpt separator that is used to detect the excerpt. A
common choice would be . If the separator is not found, excerptAst
falls back to pruneLength (default undefined).
- omission: the omission text to add after the excerpt (default …`)

Contributors

- Dillon Parfitt (DParfitt)