GraphQLParser.js

function parseAttrs (str) {
  str = str.replace('(', '')
  str = str.replace(')', '')
  let parts =  str.split(':')
  let tmp = {}
  if (parts[0] && parts[1]) {
    let v = parts[1].trim()
    v = v.replace(/\'/g, '')
    if (!isNaN(v)) {
      v = parseFloat(v)
    }
    tmp[parts[0].trim()] = v
  }
  return tmp
}

function parsePart (str) {
  str = str.replace('{', '')
  str = str.replace('}', '')
}

function parse(str) {
  str = str.replace(/[\r\n]/g, '')
  str = str.trim()
  let result = {}
  let fieldsStart = str.indexOf('{')
  let fieldsEnd = str.lastIndexOf('}')
  let nameAttrs = str.substr(0, fieldsStart)
  nameAttrs = nameAttrs.trim()
  if (nameAttrs[nameAttrs.length - 1] === ':') {
    nameAttrs = nameAttrs.substr(0, nameAttrs.length - 1)
  }
  // 是否有 attrs
  let attrStart = nameAttrs.indexOf('(')
  if (attrStart !== -1) {
    result.attrs = {
      data: parseAttrs(nameAttrs.substr(attrStart))
    }
    nameAttrs = nameAttrs.substr(0, attrStart)
    result.type = nameAttrs

    // 检查条件
    let subPart = str.substr(attrStart)
    subPart = subPart.trim()
    if (subPart[0] === '(') {
      let attrsPart = subPart.substr(0, subPart.indexOf(')') + 1)
      attrsPart = attrsPart.trim()
      result.attrs = {
        data: parseAttrs(attrsPart)
      }
      subPart = subPart.substr(subPart.indexOf(')') + 1)
    }
    subPart = subPart.trim()
    if (subPart[0] === ':') {
      subPart = subPart.substr(1)
    }
    subPart = subPart.trim()
    subPart = subPart.substr(1, subPart.length - 2)
    
    // 检查字段
    let relationStart = subPart.indexOf('{')
    if (relationStart === -1) {
      result.fields = subPart.split(',')
    } else {
      // 检查子查询
      relationStart = subPart.lastIndexOf(',', relationStart)
      // console.log('subPart.substr(0, relationStart)', subPart, '---', subPart.substr(0, relationStart))
      result.fields = subPart.substr(0, relationStart).split(',')
      let relationPart = subPart.substr(relationStart + 1)
      relationPart = relationPart.trim()
      let relationName = ''
      if (relationPart.indexOf(' ') < relationPart.indexOf('(')) {
        relationName = relationPart.substr(0, relationPart.indexOf(' '))
        relationPart = relationPart.substr(relationPart.indexOf(' '))
      } else {
        relationName = relationPart.substr(0, relationPart.indexOf('('))
      }
      if (relationName) {
        if (!result.relations) {
          result.relations = {}
        }
        result.relations[relationName] = {
          name: relationName,
          target: parse(relationPart)
        }
      }
    }
  }
  if (result.fields && result.fields.length) {
    result.fields = result.fields.map(f => f.trim())
  }
  return result
}

const inputStr = `User( age:21 ){
  id,
  name,
assigned Task( content: 'run' ): {
    id,
    content
  }
}`

// console.log(parseAttrs('(   s :  1 )'))
console.log(JSON.stringify(parse(inputStr)))