result.js

let Warning = require('./warning')

/**
 * Provides the result of the PostCSS transformations.
 *
 * A Result instance is returned by {@link LazyResult#then}
 * or {@link Root#toResult} methods.
 *
 * @example
 * postcss([autoprefixer]).process(css).then(result => {
 *  console.log(result.css)
 * })
 *
 * @example
 * const result2 = postcss.parse(css).toResult()
 */
class Result {
  /**
   * @param {Processor} processor Processor used for this transformation.
   * @param {Root}      root      Root node after all transformations.
   * @param {processOptions} opts Options from the {@link Processor#process}
   *                              or {@link Root#toResult}.
   */
  constructor (processor, root, opts) {
    /**
     * The Processor instance used for this transformation.
     *
     * @type {Processor}
     *
     * @example
     * for (const plugin of result.processor.plugins) {
     *   if (plugin.postcssPlugin === 'postcss-bad') {
     *     throw 'postcss-good is incompatible with postcss-bad'
     *   }
     * })
     */
    this.processor = processor
    /**
     * Contains messages from plugins (e.g., warnings or custom messages).
     * Each message should have type and plugin properties.
     *
     * @type {Message[]}
     *
     * @example
     * postcss.plugin('postcss-min-browser', () => {
     *   return (root, result) => {
     *     const browsers = detectMinBrowsersByCanIUse(root)
     *     result.messages.push({
     *       type: 'min-browser',
     *       plugin: 'postcss-min-browser',
     *       browsers
     *     })
     *   }
     * })
     */
    this.messages = []
    /**
     * Root node after all transformations.
     *
     * @type {Root}
     *
     * @example
     * root.toResult().root === root
     */
    this.root = root
    /**
     * Options from the {@link Processor#process} or {@link Root#toResult} call
     * that produced this Result instance.
     *
     * @type {processOptions}
     *
     * @example
     * root.toResult(opts).opts === opts
     */
    this.opts = opts
    /**
     * A CSS string representing of {@link Result#root}.
     *
     * @type {string}
     *
     * @example
     * postcss.parse('a{}').toResult().css //=> "a{}"
     */
    this.css = undefined
    /**
     * An instance of `SourceMapGenerator` class from the `source-map` library,
     * representing changes to the {@link Result#root} instance.
     *
     * @type {SourceMapGenerator}
     *
     * @example
     * result.map.toJSON() //=> { version: 3, file: 'a.css', … }
     *
     * @example
     * if (result.map) {
     *   fs.writeFileSync(result.opts.to + '.map', result.map.toString())
     * }
     */
    this.map = undefined
  }

  /**
   * Returns for @{link Result#css} content.
   *
   * @example
   * result + '' === result.css
   *
   * @return {string} String representing of {@link Result#root}.
   */
  toString () {
    return this.css
  }

  /**
   * Creates an instance of {@link Warning} and adds it
   * to {@link Result#messages}.
   *
   * @param {string} text        Warning message.
   * @param {Object} [opts]      Warning options.
   * @param {Node}   opts.node   CSS node that caused the warning.
   * @param {string} opts.word   Word in CSS source that caused the warning.
   * @param {number} opts.index  Index in CSS node string that caused
   *                             the warning.
   * @param {string} opts.plugin Name of the plugin that created
   *                             this warning. {@link Result#warn} fills
   *                             this property automatically.
   *
   * @return {Warning} Created warning.
   */
  warn (text, opts = { }) {
    if (!opts.plugin) {
      if (this.lastPlugin && this.lastPlugin.postcssPlugin) {
        opts.plugin = this.lastPlugin.postcssPlugin
      }
    }

    let warning = new Warning(text, opts)
    this.messages.push(warning)

    return warning
  }

  /**
     * Returns warnings from plugins. Filters {@link Warning} instances
     * from {@link Result#messages}.
     *
     * @example
     * result.warnings().forEach(warn => {
     *   console.warn(warn.toString())
     * })
     *
     * @return {Warning[]} Warnings from plugins.
     */
  warnings () {
    return this.messages.filter(i => i.type === 'warning')
  }

  /**
   * An alias for the {@link Result#css} property.
   * Use it with syntaxes that generate non-CSS output.
   *
   * @type {string}
   *
   * @example
   * result.css === result.content
   */
  get content () {
    return this.css
  }
}

module.exports = Result

/**
 * @typedef  {object} Message
 * @property {string} type   Message type.
 * @property {string} plugin Source PostCSS plugin name.
 */