javascript - 重构 KnexJS 多重 Promise

Question

我正在使用 Knexjs 和 Promise 运行多个选择查询。我需要所有查询在发送结果之前返回一个值，我已经能够实现这一点。但是我不认为代码非常优化。

knex(table).select('CRMContactId').where('FCIRecognition', '<', -49.00)
            .then(function(results) {

                data.largeclawbacks = results.length;

                knex(table).select('CRMContactId').where('PlanStatus', 'Out of Force').andWhere(function(){this.whereNot('IncomeType', 'Fund Based Commission').andWhereNot('IncomeType', 'Renewal Commission')})
                    .then(function(results) {

                        data.outofforce = results.length;

                        knex(table).select('CRMContactId').where('GroupOneCaption', 'Tier 2').andWhereNot('Payaways Made/Received', 'Payaway Made')
                            .andWhere((builder) => builder.whereIn('Plantype', ['Flexible Benefits','General Insurance','Group Critical Illness','Group Death In Service','Group Dental Insurance','Group Healthcare Cash Plan','Group Income Protection','Group Life','Group Life;Group Income Protection','Group PMI','Group Travel Insurance']))
                            .andWhereNot('Payable', 0)
                            .then(function(results) {

                                data.tier2 = results.length;

                                knex(table).select('CRMContactId').where((builder) => builder.where('GroupOneCaption', 'Tier 3').orWhere('GroupOneCaption', 'Tier 4')).
                                andWhereNot('Payaways Made/Received', 'Payaway Made')
                                    .andWhere((builder) => builder.whereIn('Plantype', ['Accident Sickness & Unemployment Insurance','AVC','Discretionary Managed Service','Endowment','Enhanced Pension Annuity','Executive Pension Plan','FSAVC','General Investment Account','Income Drawdown','Income Protection','Individual Retirement Account', 'Insurance / Investment Bond','Investment Trust','ISA','Long Term Care','Maximum Investment Plan','Money Purchase Contracted','OEIC / Unit Trust','Offshore Bond','Pension Annuity','Pension Term Assurance','Personal Equity Plan','Personal Pension Plan','Regular Savings Plan','Relevant Life Policy','s226 RAC','s32 Buyout Bond','Savings Account','SIPP','SSAS','Stakeholder Individual','Term Protection','Venture Capital Trust','Whole Of Life','Wrap']))
                                    .andWhereNot('Payable', 0)
                                    .then(function(results) {

                                        data.tier3 = results.length;

                                        knex(table).select('CRMContactId').where('FCIRecognition', '>', 500.00).andWhere('IncomeType', 'Renewal Commission')
                                            .then(function(results) {

                                                data.largerenewal = results.length;

                                                knex.raw(`SELECT ContactName AS Adviser, FORMAT(SUM(Payable),2) AS 'Renewal Income' FROM fci_test WHERE IncomeType IN ("Renewal Commission","Fund Based Commission","Ongoing Fee") AND \`Payaways Made/Received\` != 'Payaway Made' GROUP BY ContactName`)
                                                    .then(function(results){

                                                        data.renewalincome = results[0];
                                                        res.send(data)
                                                    })

                                            })
                                    })
                            })
                    })
            })

我确信有更好的方法来编码并获得相同的结果。

Answer 1

我首先关心的是可读性，然后才是性能。 首先使代码更具可读性，更容易看出可以应用哪种优化。

经过一些重构，我们可以得到类似于以下的代码:

knex(table).select('CRMContactId')
  .where('FCIRecognition', '<', -49.00)
  .then(function(results) {

    data.largeclawbacks = results.length;

    knex(table).select('CRMContactId')
      .where('PlanStatus', 'Out of Force')
      .andWhere((builder) => {
        builder.whereNot('IncomeType', 'Fund Based Commission')
          .andWhereNot('IncomeType', 'Renewal Commission');
      })
      .then(function(results) {

        data.outofforce = results.length;

        knex(table).select('CRMContactId')
          .where('GroupOneCaption', 'Tier 2')
          .andWhereNot('Payaways Made/Received', 'Payaway Made')
          .whereIn('Plantype', tier2PlanTypes)
          .andWhereNot('Payable', 0)
          .then(function(results) {

            data.tier2 = results.length;

            knex(table).select('CRMContactId')
              .whereIn('GroupOneCaption', ['Tier 3', 'Tier 4'])
              .andWhereNot('Payaways Made/Received', 'Payaway Made')
              .whereIn('Plantype', tier3PlanTypes)
              .andWhereNot('Payable', 0)
              .then(function(results) {

                data.tier3 = results.length;

                knex(table).select('CRMContactId')
                  .where('FCIRecognition', '>', 500.00)
                  .andWhere('IncomeType', 'Renewal Commission')
                  .then(function(results) {

                    data.largerenewal = results.length;

                    knex.raw(`SELECT ContactName AS Adviser, FORMAT(SUM(Payable),2) AS 'Renewal Income' FROM fci_test 
                              WHERE IncomeType IN ("Renewal Commission","Fund Based Commission","Ongoing Fee") 
                                AND \`Payaways Made/Received\` != 'Payaway Made' GROUP BY ContactName`)
                      .then(function(results){
                          data.renewalincome = results[0];
                          res.send(data)
                      });
                  })
              })
          })
      })
  });

看起来不太像，但是我可以更清楚地看到所有查询都是相互独立的(我将用它来优化)

之后，进一步重构，我将每个查询保存在一个常量中，然后使用 Promise.all 一次发出所有查询以及它们完成的方式以便发送响应。

const largeclawbacksQuery = knex(table).select('CRMContactId')
  .where('FCIRecognition', '<', -49.00);

const outofforceQuery = knex(table).select('CRMContactId')
  .where('PlanStatus', 'Out of Force')
  .andWhere((builder) => {
    builder.whereNot('IncomeType', 'Fund Based Commission')
      .andWhereNot('IncomeType', 'Renewal Commission')
  });

const tier2Query = knex(table).select('CRMContactId')
    .where('GroupOneCaption', 'Tier 2')
    .andWhereNot('Payaways Made/Received', 'Payaway Made')
    .whereIn('Plantype', tier2PlanTypes)
    .andWhereNot('Payable', 0);

const tier3Query = knex(table).select('CRMContactId')
  .whereIn('GroupOneCaption', ['Tier 3', 'Tier 4'])
  .andWhereNot('Payaways Made/Received', 'Payaway Made')
  .whereIn('Plantype', tier3PlanTypes)
  .andWhereNot('Payable', 0);

const largerenewalQuery = knex(table).select('CRMContactId')
  .where('FCIRecognition', '>', 500.00)
  .andWhere('IncomeType', 'Renewal Commission');

const renewalincomeQuery = knex.raw(
  `SELECT ContactName AS Adviser, FORMAT(SUM(Payable),2) AS 'Renewal Income' FROM fci_test 
    WHERE IncomeType IN ("Renewal Commission","Fund Based Commission","Ongoing Fee") 
      AND \`Payaways Made/Received\` != 'Payaway Made' GROUP BY ContactName`
);

Promise.all([largeclawbacksQuery, outofforceQuery, tier2Query, tier3Query, largerenewalQuery, renewalincomeQuery])
  .then((result) => {
    res.send({
      largeclawbacks: result[0].length,
      outofforce: result[1].length,
      tier2: results[2].length,
      tier3: results[3].length,
      largerenewal: results[4].length,
      renewalincome: results[4][0],
    });
  });

要点:

• whereIn 可以链接起来，它们将转换为 sql WHERE afield IN avalues AND bfield IN bvalues
• 行长可以提高可读性，从而使代码更易于阅读
• 如果我们将其视为 promise ，我们可以等待查询构建器完成其查询

进一步改进:

• 每个方法(whereIn、where、orWhere 等)都会返回一个查询构建器 可以通过克隆查询生成器实例来重用部分查询，如所述 here 。这可以帮助您定义 tier2Query 和 tier3Query 的基本查询。
• 我们可以等待使用更好的 API 来解决 promise ，例如 promise-all-properties
• 您可以直接请求 COUNT，而不是查询所有记录来获取长度值，这样可以提高性能。