Markdown parser, done right. 100% CommonMark support, extensions, syntax plugins & high speed https://markdown-it.github.io/
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/**
* class Renderer
*
* Generates HTML from parsed token stream. Each instance has independent
* copy of rules. Those can be rewritten with ease. Also, you can add new
* rules if you create plugin and adds new token types.
**/
import { assign, unescapeAll, escapeHtml } from './common/utils.mjs'
////////////////////////////////////////////////////////////////////////////////
const default_rules = {}
default_rules.code_inline = function (tokens, idx, options, env, slf) {
const token = tokens[idx]
return '<code' + slf.renderAttrs(token) + '>' +
escapeHtml(token.content) +
'</code>'
}
default_rules.code_block = function (tokens, idx, options, env, slf) {
const token = tokens[idx]
return '<pre' + slf.renderAttrs(token) + '><code>' +
escapeHtml(tokens[idx].content) +
'</code></pre>\n'
}
default_rules.fence = function (tokens, idx, options, env, slf) {
const token = tokens[idx]
const info = token.info ? unescapeAll(token.info).trim() : ''
let langName = ''
let langAttrs = ''
if (info) {
const arr = info.split(/(\s+)/g)
langName = arr[0]
langAttrs = arr.slice(2).join('')
}
let highlighted
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if (options.highlight) {
highlighted = options.highlight(token.content, langName, langAttrs) || escapeHtml(token.content)
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} else {
highlighted = escapeHtml(token.content)
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}
if (highlighted.indexOf('<pre') === 0) {
return highlighted + '\n'
}
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// If language exists, inject class gently, without modifying original token.
// May be, one day we will add .deepClone() for token and simplify this part, but
// now we prefer to keep things local.
if (info) {
const i = token.attrIndex('class')
const tmpAttrs = token.attrs ? token.attrs.slice() : []
if (i < 0) {
tmpAttrs.push([ 'class', options.langPrefix + langName ])
} else {
tmpAttrs[i] = tmpAttrs[i].slice()
tmpAttrs[i][1] += ' ' + options.langPrefix + langName
}
// Fake token just to render attributes
const tmpToken = {
attrs: tmpAttrs
}
return '<pre><code' + slf.renderAttrs(tmpToken) + '>'
+ highlighted
+ '</code></pre>\n'
}
return '<pre><code' + slf.renderAttrs(token) + '>'
+ highlighted
+ '</code></pre>\n'
}
default_rules.image = function (tokens, idx, options, env, slf) {
const token = tokens[idx]
// "alt" attr MUST be set, even if empty. Because it's mandatory and
// should be placed on proper position for tests.
//
// Replace content with actual value
token.attrs[token.attrIndex('alt')][1] =
slf.renderInlineAsText(token.children, options, env)
return slf.renderToken(tokens, idx, options)
}
default_rules.hardbreak = function (tokens, idx, options /*, env */) {
return options.xhtmlOut ? '<br />\n' : '<br>\n'
}
default_rules.softbreak = function (tokens, idx, options /*, env */) {
return options.breaks ? (options.xhtmlOut ? '<br />\n' : '<br>\n') : '\n'
}
default_rules.text = function (tokens, idx /*, options, env */) {
return escapeHtml(tokens[idx].content)
}
default_rules.html_block = function (tokens, idx /*, options, env */) {
return tokens[idx].content
}
default_rules.html_inline = function (tokens, idx /*, options, env */) {
return tokens[idx].content
}
/**
* new Renderer()
*
* Creates new [[Renderer]] instance and fill [[Renderer#rules]] with defaults.
**/
function Renderer() {
/**
* Renderer#rules -> Object
*
* Contains render rules for tokens. Can be updated and extended.
*
* ##### Example
*
* ```javascript
* var md = require('markdown-it')();
*
* md.renderer.rules.strong_open = function () { return '<b>'; };
* md.renderer.rules.strong_close = function () { return '</b>'; };
*
* var result = md.renderInline(...);
* ```
*
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* Each rule is called as independent static function with fixed signature:
*
* ```javascript
* function my_token_render(tokens, idx, options, env, renderer) {
* // ...
* return renderedHTML;
* }
* ```
*
* See [source code](https://github.com/markdown-it/markdown-it/blob/master/lib/renderer.js)
* for more details and examples.
**/
this.rules = assign({}, default_rules)
}
/**
* Renderer.renderAttrs(token) -> String
*
* Render token attributes to string.
**/
Renderer.prototype.renderAttrs = function renderAttrs(token) {
let i, l, result
if (!token.attrs) { return '' }
result = ''
for (i = 0, l = token.attrs.length; i < l; i++) {
result += ' ' + escapeHtml(token.attrs[i][0]) + '="' + escapeHtml(token.attrs[i][1]) + '"'
}
return result
}
/**
* Renderer.renderToken(tokens, idx, options) -> String
* - tokens (Array): list of tokens
* - idx (Numbed): token index to render
* - options (Object): params of parser instance
*
* Default token renderer. Can be overriden by custom function
* in [[Renderer#rules]].
**/
Renderer.prototype.renderToken = function renderToken(tokens, idx, options) {
const token = tokens[idx]
let result = ''
// Tight list paragraphs
if (token.hidden) {
return ''
}
// Insert a newline between hidden paragraph and subsequent opening
// block-level tag.
//
// For example, here we should insert a newline before blockquote:
// - a
// >
//
if (token.block && token.nesting !== -1 && idx && tokens[idx - 1].hidden) {
result += '\n'
}
// Add token name, e.g. `<img`
result += (token.nesting === -1 ? '</' : '<') + token.tag
// Encode attributes, e.g. `<img src="foo"`
result += this.renderAttrs(token)
// Add a slash for self-closing tags, e.g. `<img src="foo" /`
if (token.nesting === 0 && options.xhtmlOut) {
result += ' /'
}
// Check if we need to add a newline after this tag
let needLf = false
if (token.block) {
needLf = true
if (token.nesting === 1) {
if (idx + 1 < tokens.length) {
const nextToken = tokens[idx + 1]
if (nextToken.type === 'inline' || nextToken.hidden) {
// Block-level tag containing an inline tag.
//
needLf = false
} else if (nextToken.nesting === -1 && nextToken.tag === token.tag) {
// Opening tag + closing tag of the same type. E.g. `<li></li>`.
//
needLf = false
}
}
}
}
result += needLf ? '>\n' : '>'
return result
}
/**
* Renderer.renderInline(tokens, options, env) -> String
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* - tokens (Array): list on block tokens to render
* - options (Object): params of parser instance
* - env (Object): additional data from parsed input (references, for example)
*
* The same as [[Renderer.render]], but for single token of `inline` type.
**/
Renderer.prototype.renderInline = function (tokens, options, env) {
let result = ''
const rules = this.rules
for (let i = 0, len = tokens.length; i < len; i++) {
const type = tokens[i].type
if (typeof rules[type] !== 'undefined') {
result += rules[type](tokens, i, options, env, this)
} else {
result += this.renderToken(tokens, i, options)
}
}
return result
}
/** internal
* Renderer.renderInlineAsText(tokens, options, env) -> String
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* - tokens (Array): list on block tokens to render
* - options (Object): params of parser instance
* - env (Object): additional data from parsed input (references, for example)
*
* Special kludge for image `alt` attributes to conform CommonMark spec.
* Don't try to use it! Spec requires to show `alt` content with stripped markup,
* instead of simple escaping.
**/
Renderer.prototype.renderInlineAsText = function (tokens, options, env) {
let result = ''
for (let i = 0, len = tokens.length; i < len; i++) {
if (tokens[i].type === 'text') {
result += tokens[i].content
} else if (tokens[i].type === 'image') {
result += this.renderInlineAsText(tokens[i].children, options, env)
} else if (tokens[i].type === 'softbreak') {
result += '\n'
}
}
return result
}
/**
* Renderer.render(tokens, options, env) -> String
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* - tokens (Array): list on block tokens to render
* - options (Object): params of parser instance
* - env (Object): additional data from parsed input (references, for example)
*
* Takes token stream and generates HTML. Probably, you will never need to call
* this method directly.
**/
Renderer.prototype.render = function (tokens, options, env) {
let result = ''
const rules = this.rules
for (let i = 0, len = tokens.length; i < len; i++) {
const type = tokens[i].type
if (type === 'inline') {
result += this.renderInline(tokens[i].children, options, env)
} else if (typeof rules[type] !== 'undefined') {
result += rules[type](tokens, i, options, env, this)
} else {
result += this.renderToken(tokens, i, options, env)
}
}
return result
}
export default Renderer