var pkg = require('../package.json')
var api = require('./api.js')
var parser = require('posthtml-parser')
var render = require('posthtml-render')
/**
* @author Ivan Voischev (@voischev),
* Anton Winogradov (@awinogradov),
* Alexej Yaroshevich (@zxqfox),
* Vasiliy (@Yeti-or)
*
* @requires api
* @requires posthtml-parser
* @requires posthtml-render
*
* @constructor PostHTML
* @param {Array} plugins - An array of PostHTML plugins
*/
function PostHTML (plugins) {
/**
* PostHTML Instance
*
* @prop plugins
* @prop options
*/
this.version = pkg.version
this.name = pkg.name
this.plugins = typeof plugins === 'function' ? [plugins] : plugins || []
}
/**
* @requires posthtml-parser
*
* @param {String} html - Input (HTML)
* @returns {Array} tree - PostHTMLTree (JSON)
*/
PostHTML.parser = parser
/**
* @requires posthtml-render
*
* @param {Array} tree - PostHTMLTree (JSON)
* @returns {String} html - HTML
*/
PostHTML.render = render
/**
* @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))
* ```
*/
PostHTML.prototype.use = function () {
[].push.apply(this.plugins, arguments)
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))
* ```
*/
PostHTML.prototype.process = function (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
*/
options = options || {}
if (options.parser) parser = options.parser
if (options.render) render = options.render
tree = options.skipParse ? tree : parser(tree)
tree.options = options
tree.processor = this
// sync mode
if (options.sync === true) {
this.plugins.forEach(function (plugin) {
apiExtend(tree)
var 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
)
}
// return the previous tree unless result is fulfilled
tree = result || tree
})
return lazyResult(render, tree)
}
// async mode
var i = 0
var next = function (result, cb) {
// all plugins called
if (this.plugins.length <= i) {
cb(null, result)
return
}
// little helper to go to the next iteration
function _next (res) {
return next(res || result, cb)
}
// (re)extend the object
apiExtend(result)
// call next
var plugin = this.plugins[i++]
if (plugin.length === 2) {
plugin(result, function (err, res) {
if (err) return cb(err)
_next(res)
})
return
}
// sync and promised plugins
var err = null
var res = tryCatch(function () {
return plugin(result)
}, function (err) {
return err
})
if (err) {
cb(err)
return
}
if (isPromise(res)) {
res.then(_next).catch(cb)
return
}
_next(res)
}.bind(this)
return new Promise(function (resolve, reject) {
next(tree, function (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 = function (plugins) {
return new PostHTML(plugins)
}
/**
* 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)
}
}
/**
* Extends the PostHTMLTree with the Tree API
*
* @private
*
* @param {Array} tree - PostHTMLTree
* @returns {Array} tree - PostHTMLTree with API
*/
function apiExtend (tree) {
tree.walk = api.walk
tree.match = api.match
}
/**
* 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: tree
}
}