Node.js 如何使用钩子在字段表中添加计算？

假设我有一个包含三个字段的表，“id”、“firstValue”和“secondValue”。我使用postgres作为它的数据库。我想先添加一些计算，例如，第二个字段“firstValue”应该是（firstValue+secondValue）/10。有人知道如何在hooks服务中添加此计算吗？有人能在hooks中给出一个方法示例吗

这是hooks服务中的模板

module.exports = function () {
    return async context => {


      return context;
    };
  };

我将此文件保存为calculate.js

这是hooks.js中的模板

let calculate = require('./../../hooks/calculate');

module.exports = {
  before: {
    all: [],
    find: [calculate()], // add some calculation  
    get: [calculate()], // add some calculation 
    create: [],
    update: [],
    patch: [],
    remove: []
  },

  after: {
    all: [],
    find: [],
    get: [],
    create: [],
    update: [],
    patch: [],
    remove: []
  },

  error: {
    all: [],
    find: [],
    get: [],
    create: [],
    update: [],
    patch: [],
    remove: []
  }
};

---

感谢上下文。result是表示服务调用结果的对象（此处提到：），可以在after hook中访问它。那么你的钩子应该是：

module.exports = function () {
    return async context => {
        context.result.computedField = ( context.result.firstValue + context.result.secondValue ) / 10

      return context;
    };
};

let calculate = require('./../../hooks/calculate');

module.exports = {
  before: {
    all: [],
    find: [], 
    get: [],
    create: [],
    update: [],
    patch: [],
    remove: []
  },

  after: {
    all: [],
    find: [calculate()],
    get: [calculate()],
    create: [],
    update: [],
    patch: [],
    remove: []
  },

  error: {
    all: [],
    find: [],
    get: [],
    create: [],
    update: [],
    patch: [],
    remove: []
  }
};

钩子文件应该是：

module.exports = function () {
    return async context => {
        context.result.computedField = ( context.result.firstValue + context.result.secondValue ) / 10

      return context;
    };
};

let calculate = require('./../../hooks/calculate');

module.exports = {
  before: {
    all: [],
    find: [], 
    get: [],
    create: [],
    update: [],
    patch: [],
    remove: []
  },

  after: {
    all: [],
    find: [calculate()],
    get: [calculate()],
    create: [],
    update: [],
    patch: [],
    remove: []
  },

  error: {
    all: [],
    find: [],
    get: [],
    create: [],
    update: [],
    patch: [],
    remove: []
  }
};