如何使JavaScript 代碼庫更干凈 5種方法告訴你

 更新時間:2021年09月10日 08:44:21   作者:vue_fe  
J avaScript無處不在,從PC端到移動設備端,甚至是后端,都在使用JavaSc ript。在本文中,將嘗試一些可用來使代碼看起來更簡潔的實踐方案,希望能幫助到大家

1、使用默認參數代替短路或條件

默認參數通常比短路更干凈。

function SomeMethod(paramThatCanBeUndefined) {

   const localValue = paramThatCanBeUndefined || "Default Value";
   console.log(localValue)
   // ...
}
SomeMethod() // Default Value
SomeMethod("SomeValue") // SomeValue

嘗試以下方法:

function SomeMethod(
  console.log(paramThatCanBeUndefined)
  // ...
}
SomeMethod() // Default Value
SomeMethod("SomeValue") // SomeValue

聲明:Falsy值,如'',"",false,null,0,和NaN將不會被默認值替代:

function SomeMethod(paramThatCanBeUndefined = "Default Value") {        
  console.log(paramThatCanBeUndefined)  
  // ...
}
SomeMethod(null) // will not Default Value, will null Instead
SomeMethod("SomeValue") // SomeValue

2、處理多個條件

const conditions = ["Condition 2","Condition String2"];
someFunction(str){
  if(str.includes("someValue1") || str.includes("someValue2")){
    return true
  }else{
    return false
  }
}

一種更干凈的方法是:

someFunction(str){
   const conditions = ["someValue1","someValue2"];
   return conditions.some(condition=>str.includes(condition));
}

3、用動態鍵值對替換開關(即對象文字)

開關版本(或將開關替換為if / else):

const UserRole = {
  ADMIN: "Admin",
  GENERAL_USER: "GeneralUser",
  SUPER_ADMIN: "SuperAdmin",
};
function getRoute(userRole = "default role"){


  switch(userRole){
    case UserRole.ADMIN:
      return "/admin"
    case UserRole.GENERAL_USER:
        return "/GENERAL_USER"
    case UserRole.SUPER_ADMIN:
        return "/superadmin"
    default:
      return "/" 
  }

}
console.log(getRoute(UserRole.ADMIN)) // return "/admin"
console.log(getRoute("Anything")) // return Default path
console.log(getRoute()) // return Default path
console.log(getRoute(null)) // return Default path

// More cases if new arrive
// You can think if else instead of switch

動態鍵值對版本:

const UserRole = {
   ADMIN: "Admin",
   GENERAL_USER: "GeneralUser",
   SUPER_ADMIN: "SuperAdmin",
};
function getRoute(userRole = "default role"){
 const appRoute = {
  [UserRole.ADMIN]: "/admin",
  [UserRole.GENERAL_USER]: "/user",
  [UserRole.SUPER_ADMIN]: "/superadmin"
 };
 return appRoute[userRole] || "Default path";
}
console.log(getRoute(UserRole.ADMIN)) // return "/admin"
console.log(getRoute("Anything")) // return Default path
console.log(getRoute()) // return Default path
console.log(getRoute(null)) // return Default path
// No more switch/if-else here.
// Easy to Further expansion

4、避免過多的函數參數

function myFunction(employeeName,jobTitle,yrExp,majorExp){
 return `${employeeName} is working as ${jobTitle} with ${yrExp}    years of experience in ${majorExp}`
}
//output be like John is working as Project Manager with 12 year of experience in Project Management
// you can call it via
console.log(myFunction("John","Project Manager",12,"Project Management"))
//    ***** PROBLEMS ARE *****
// Violation of 'clean code' principle
// Parameter sequencing is important
// Unused Params warning if not used
// Testing need to consider a lot of edge cases.

這是一種更清潔的方法:

function myFunction({employeeName,jobTitle,yrExp,majorExp}){
 return `${employeeName} is working as ${jobTitle} with ${yrExp} years of experience in ${majorExp}`
}
//output be like John is working as Project Manager with 12 year of experience in Project Management
// you can call it via
const mockTechPeople = {
  employeeName:"John",
  jobTitle:"Project Manager",
  yrExp:12,
  majorExp:"Project Management"
}
console.log(myFunction(mockTechPeople))
// ES2015/ES6 destructuring syntax is in action
// map your desired value to variable you need.

5、使用Object.assign設置默認對象

這看起來很繁瑣:

const someObject = {
 title: null,
 subTitle: "Subtitle",
 buttonColor: null,
 disabled: true
};
function createOption(someObject) {
 someObject.title = someObject.title || "Default Title";
 someObject.subTitle = someObject.subTitle || "Default Subtitle";
 someObject.buttonColor = someObject.buttonColor || "blue";
 someObject.disabled = someObject.disabled !== undefined ?  someObject.disabled : true;
 return someObject
}
console.log(createOption(someObject));

// Output be like 
// {title: 'Default Title', subTitle: 'Subtitle', buttonColor: 'blue', disabled: true}

這種方法看起來更好:

const someObject = {
  title: null,
  subTitle: "Subtitle",
  buttonColor: null,
  disabled: true
 };
 function creteOption(someObject) {
  const newObject = Object.assign({
   title: "Default Title",
   subTitle: "Default Subtitle",
   buttonColor: "blue",
   disabled: true
 },someObject)
 return newObject
 }
 console.log(creteOption(someObject));

到此這篇關于如何使JavaScript 代碼庫更干凈 5種方法告訴你的文章就介紹到這了,更多相關使 JavaScript 代碼庫更干凈的5種方法內容請搜索腳本之家以前的文章或繼續瀏覽下面的相關文章希望大家以后多多支持腳本之家!謝謝大家的閱讀

相關文章

最新評論

精品国内自产拍在线观看