docs: function analyze (entry, options) {
    options = options || {}
  
    let result = {}
  
    // support array
    if (!Array.isArray(entry)) {
      entry = [entry]
    }
  
    entry.forEach(file => {
      let content
  
      // normalize file
      if (typeof file === 'string') {
        content = fs.readFileSync(file, 'utf8')
      } else {
        content = file.content
        file = file.file
      }
  
      let filter = options.filter
      let depResolve = options.depResolve
      let depth = options.depth
  
      analyzeFile(file, content, filter, depResolve, depth, result)
    })
  
    return result
  }