19 JSON stringifier

json_stringifier.js

function json_stringify(json, indent) {
  var str = ''
  var stack_dep = 0

  function getSpaces(length) {
    var spaces = new Array(length)
    spaces.fill(' ')
    return spaces.join('')
  }

  function stringifyElement(node) {
    if (typeof node == 'number') {
      return stringifyNumber(node)
    } else if (typeof node == 'string') {
      return stringifyString(node)
    } else if (typeof node == 'boolean') {
      return stringifyBoolean(node)
    } else if (node === null) {
      return stringifyNull(node)
    } else if (node.constructor.name == 'Array') {
      return stringifyArray(node)
    } else if (typeof node == 'object' && node.constructor.name != 'Array') {
      return stringifyObject(node)
    }
  }

  function stringifyNumber(node) {
    return node.toString()
  }

  function stringifyString(node) {
    return '"' + node + '"'
  }

  function stringifyBoolean(node) {
    return node.toString()
  }

  function stringifyNull(node) {
    return 'null'
  }

  function stringifyArray(node) {
    var str = '['
    if (node.length > 0) {
      stack_dep++
    }
    if (indent > 0) {
      str += '\n'
    }
    for (var i = 0; i < node.length; i++) {
      if (indent > 0) {
        str += getSpaces(stack_dep * indent)
      }
      str += stringifyElement(node[i])
      if ((indent > 0, i <= node.length - 2) || (!indent && i <= node.length - 1)) {
        str += ","
      }
      if (indent > 0) {
        str += '\n'
      }
    }
    if (node.length > 0) {
      stack_dep--
    }
    if (indent > 0) {
      str += getSpaces(stack_dep * indent)
      str += '\n'
    }
    str = str.slice(0, -1)
    str += ']'
    return str
  }

  function stringifyObject(node) {
    var str = '{'
    var keys = Object.keys(node)
    if (keys.length > 0) {
      stack_dep++
    }
    if (indent > 0) {
      str += '\n'
    }
    for (var i = 0; i < keys.length; i++) {
      var key = keys[i]
      var value = node[key]
      if (indent > 0) {
        str += getSpaces(stack_dep * indent)
      }
      str += '"' + key + '"'
      str += ":"
      if (indent > 0) {
        str += ' '
      }
      str += stringifyElement(value)
      if ((indent > 0, i <= keys.length - 2) || (!indent && i <= keys.length - 1)) {
        str += ","
      }
      if (indent > 0) {
        str += '\n'
      }
    }
    if (keys.length > 0) {
      stack_dep--
    }
    if (indent > 0) {
      str += getSpaces(stack_dep * indent)
      str += '\n'
    }
    str = str.slice(0, -1)
    str += "}"
    return str
  }

  return stringifyElement(json)
}