vuepress/lib/util.js

exports.normalizeHeadTag = tag => {
  if (typeof tag === 'string') {
    tag = [tag]
  }
  const tagName = tag[0]
  return {
    tagName,
    attributes: tag[1] || {},
    innerHTML: tag[2] || '',
    closeTag: !(tagName === 'meta' || tagName === 'link')
  }
}

exports.applyUserWebpackConfig = function (userConfig, config, isServer) {
  const merge = require('webpack-merge')
  if (typeof userConfig === 'object') {
    return merge(config, userConfig)
  }
  if (typeof userConfig === 'function') {
    const res = userConfig(config, isServer)
    if (res && typeof res === 'object') {
      return merge(config, res)
    }
  }
  return config
}

exports.inferTitle = function (frontmatter) {
  if (frontmatter.title) {
    return frontmatter.title
  }
  const match = frontmatter.__content.trim().match(/^#+\s+(.*)/)
  if (match) {
    return match[1]
  }
}