const pkg = require('../package.json')
const Api = require('./api.js')
let { parser } = require('posthtml-parser')
let { render } = require('posthtml-render')
/**
* @author Ivan Voischev (@voischev),
* Ivan Demidov (@scrum)
*
* @requires api
* @requires posthtml-parser
* @requires posthtml-render
*
* @constructor PostHTML
* @param {Array} plugins - An array of PostHTML plugins
*/
class PostHTML {
constructor (plugins) {
/**
* PostHTML Instance
*
* @prop plugins
* @prop options
*/
this.version = pkg.version
this.name = pkg.name
this.plugins = typeof plugins === 'function' ? [plugins] : plugins || []
this.source = ''
/**
* Tree messages to store and pass metadata between plugins
*
* @memberof tree
* @type {Array} messages
*
* @example
* ```js
* export default function plugin (options = {}) {
* return function (tree) {
* tree.messages.push({
* type: 'dependency',
* file: 'path/to/dependency.html',
* from: tree.options.from
* })
*
* return tree
* }
* }
* ```
*/
this.messages = []
/**
* Tree method parsing string inside plugins.
*
* @memberof tree
* @type {Function} parser
*
* @example
* ```js
* export default function plugin (options = {}) {
* return function (tree) {
* tree.match({ tag: 'include' }, function(node) {
* node.tag = false;
* node.content = tree.parser(fs.readFileSync(node.attr.src))
* return node
* })
*
* return tree
* }
* }
* ```
*/
this.parser = parser
/**
* Tree method rendering tree to string inside plugins.
*
* @memberof tree
* @type {Function} render
*
* @example
* ```js
* export default function plugin (options = {}) {
* return function (tree) {
* var outherTree = ['\n', {tag: 'div', content: ['1']}, '\n\t', {tag: 'div', content: ['2']}, '\n'];
* var htmlWitchoutSpaceless = tree.render(outherTree).replace(/[\n|\t]/g, '');
* return tree.parser(htmlWitchoutSpaceless)
* }
* }
* ```
*/
this.render = render
// extend api methods
Api.call(this)
}
/**
* @this posthtml
* @param {Function} plugin - A PostHTML plugin
* @returns {Constructor} - this(PostHTML)
*
* **Usage**
* ```js
* ph.use((tree) => { tag: 'div', content: tree })
* .process('<html>..</html>', {})
* .then((result) => result))
* ```
*/
use (...args) {
this.plugins.push(...args)
return this
}
/**
* @param {String} html - Input (HTML)
* @param {?Object} options - PostHTML Options
* @returns {Object<{html: String, tree: PostHTMLTree}>} - Sync Mode
* @returns {Promise<{html: String, tree: PostHTMLTree}>} - Async Mode (default)
*
* **Usage**
*
* **Sync**
* ```js
* ph.process('<html>..</html>', { sync: true }).html
* ```
*
* **Async**
* ```js
* ph.process('<html>..</html>', {}).then((result) => result))
* ```
*/
process (tree, options = {}) {
/**
* ## PostHTML Options
*
* @type {Object}
* @prop {?Boolean} options.sync - enables sync mode, plugins will run synchronously, throws an error when used with async plugins
* @prop {?Function} options.parser - use custom parser, replaces default (posthtml-parser)
* @prop {?Function} options.render - use custom render, replaces default (posthtml-render)
* @prop {?Boolean} options.skipParse - disable parsing
* @prop {?Array} options.directives - Adds processing of custom [directives](https://github.com/posthtml/posthtml-parser#directives).
*/
this.options = options
this.source = tree
if (options.parser) parser = this.parser = options.parser
if (options.render) render = this.render = options.render
tree = options.skipParse
? tree || []
: parser(tree, options)
tree = [].concat(tree)
// sync mode
if (options.sync === true) {
this.plugins.forEach((plugin, index) => {
_treeExtendApi(tree, this)
let result
if (plugin.length === 2 || isPromise(result = plugin(tree))) {
throw new Error(
`Can’t process contents in sync mode because of async plugin: ${plugin.name}`
)
}
// clearing the tree of options
if (index !== this.plugins.length - 1 && !options.skipParse) {
tree = [].concat(tree)
}
// return the previous tree unless result is fulfilled
tree = result || tree
})
return lazyResult(render, tree)
}
// async mode
let i = 0
const next = (result, cb) => {
_treeExtendApi(result, this)
// all plugins called
if (this.plugins.length <= i) {
cb(null, result)
return
}
// little helper to go to the next iteration
function _next (res) {
if (res && !options.skipParse) {
res = [].concat(res)
}
return next(res || result, cb)
}
// call next
const plugin = this.plugins[i++]
if (plugin.length === 2) {
plugin(result, (err, res) => {
if (err) return cb(err)
_next(res)
})
return
}
// sync and promised plugins
let err = null
const res = tryCatch(() => plugin(result), e => {
err = e
return e
})
if (err) {
cb(err)
return
}
if (isPromise(res)) {
res.then(_next).catch(cb)
return
}
_next(res)
}
return new Promise((resolve, reject) => {
next(tree, (err, tree) => {
if (err) reject(err)
else resolve(lazyResult(render, tree))
})
})
}
}
/**
* @exports posthtml
*
* @param {Array} plugins
* @return {Function} posthtml
*
* **Usage**
* ```js
* import posthtml from 'posthtml'
* import plugin from 'posthtml-plugin'
*
* const ph = posthtml([ plugin() ])
* ```
*/
module.exports = plugins => new PostHTML(plugins)
/**
* Extension of options tree
*
* @private
*
* @param {Array} tree
* @param {Object} PostHTML
* @returns {?*}
*/
function _treeExtendApi (t, _t) {
if (typeof t === 'object') {
t = Object.assign(t, _t)
}
}
/**
* Checks if parameter is a Promise (or thenable) object.
*
* @private
*
* @param {*} promise - Target `{}` to test
* @returns {Boolean}
*/
function isPromise (promise) {
return !!promise && typeof promise.then === 'function'
}
/**
* Simple try/catch helper, if exists, returns result
*
* @private
*
* @param {Function} tryFn - try block
* @param {Function} catchFn - catch block
* @returns {?*}
*/
function tryCatch (tryFn, catchFn) {
try {
return tryFn()
} catch (err) {
catchFn(err)
}
}
/**
* Wraps the PostHTMLTree within an object using a getter to render HTML on demand.
*
* @private
*
* @param {Function} render
* @param {Array} tree
* @returns {Object<{html: String, tree: Array}>}
*/
function lazyResult (render, tree) {
return {
get html () {
return render(tree, tree.options)
},
tree,
messages: tree.messages
}
}