Json object format for highlight.js and append field comment

jsonformat.js

import _ from 'lodash'

export function jsonformat(body) {
  let htmlBlock = ''
  let space = '  '
  let index = 0
  let last = false
  let toString = Object.prototype.toString
  let self = this

  body = JSON.parse(JSON.stringify(body))

  htmlBlock += build(body, 1)

  function build(data, level) {
    let _level = level + 1
    let html = ''
    let isArrayData = Array.isArray(data)

    for (let attr in data) {
      let value = data[attr]
      let valueType = getType(value)

      if (valueType === 'array') {
        let htmlArray = ''

        htmlArray += buildAttr(attr, level) + ': ['

        if (value.length === 0) {
          htmlArray += '],' + buildComment(attr) + '\n'
        } else {
          htmlArray += buildComment(attr) + '\n'
          htmlArray += build(value, _level)
          htmlArray = _.trimEnd(htmlArray, '\n')
          htmlArray = _.trimEnd(htmlArray, ',')
          htmlArray += buildEndChar(']', level)
        }

        html += htmlArray
      } else if (valueType === 'object') {
        let htmlObject = ''
        let empty = Object.keys(value).length === 0

        htmlObject += isArrayData ? (padding(level) + '{') : (buildAttr(attr, level) + ': {')

        if (empty) {
          htmlObject += ',' + buildComment(attr) + '\n'
        } else {
          htmlObject += buildComment(attr) + '\n'
          htmlObject += build(value, _level)
          htmlObject = _.trimEnd(htmlObject, '\n')
          htmlObject = _.trimEnd(htmlObject, ',')
          htmlObject += buildEndChar('}', level)
        }

        html += htmlObject
      } else {
        html += (isArrayData ? padding(level) : (buildAttr(attr, level) + ': ')) + buildValue(valueType, value) + ',' + buildComment(attr) + '\n'
      }

      index++
    }

    return html
  }

  function getType(value) {
    return /\[object (\w+)\]/g.exec(toString.call(value))[1].toLowerCase()
  }

  function buildAttr(attr, level) {
    return padding(level) + '<span class="hljs-attr">' + attr + '</span>'
  }

  function buildValue(type, value) {
    value = type === 'string' ? '"' + value + '"' : value
    type = type === 'null' ? 'literal' : type
    return '<span class="hljs-' + type + '">' + value + '</span>'
  }

  function buildComment(attr) {
    let result = ''

    self.fields.forEach(field => {
      if (field.name === attr) {
        result = '<span class="hljs-comment"> // ' + field.description + '</span>'
      }
    })

    return result
  }

  function buildEndChar(char, level) {
    return '\n' + padding(level) + '<span>' + char + '</span>,\n'
  }

  function padding(level) {
    let result = ''

    for (let i = 0; i < level; i++) {
      result += space
    }

    return result
  }

  htmlBlock = _.trimEnd(htmlBlock, '\n')
  htmlBlock = _.trimEnd(htmlBlock, ',')

  htmlBlock = '{\n' + htmlBlock + '\n}'

  return htmlBlock
}