"JavaScript design pattern and Development practice" the template method pattern of reading notes

1. Template Method mode 1.1 object-oriented implementation of template method pattern

Take tea and coffee for example, can be organized into the following four steps

• Boil the water
• Brew a drink in boiling water
• Pour the drink into the cup
• Add seasoning

First, create an abstract parent class to represent a drink.

varBeverage=function(){}; Beverage.prototype.boilWater=function() {Console.log (' Boil the water ');}; Beverage.prototype.brew=function(){};//empty method, overridden by subclassesbeverage.prototype.pourincup=function(){};//empty method, overridden by subclassesbeverage.prototype.addcondiments=function(){};//empty method, overridden by subclassesbeverage.prototype.init=function(){     This. Boilwater ();  This. Brew ();  This. Pourincup ();  This. addcondiments ();};

Next, create the coffee subclass and tea sub-class

var coffee=function() {}; Coffee.prototype=new beverage ();

Overriding the abstract method of the parent class

coffee.prototype.brew=function() {    console.log (' brew coffee with boiling water ');}; Coffee.prototype.pourInCup=function() {    console.log (' Pour the coffee into the cup '); Coffee.prototype.addCondiments=function() {    Console.log (' Add sugar and milk ');}; var coffee=New  Coffee (); Coffee.init ();

Continue to create tea class

var tea=function() {}; Tea.prototype=new  beverage (); Tea.prototype.brew=function() {    console.log (' soak tea with boiling water ');}; Tea.prototype.pourInCup=function() {    console.log (' Pour the tea into the cup '); Tea.prototype.addCondiments=function() {    console.log (' plus lemon ');}; var tea=New  tea (); Tea.init ();

In the above example,Beverage.prototype.init is a template method that encapsulates the algorithm framework for subclasses
It serves as a template for an algorithm that instructs the subclass in what order to execute which methods

1.2 Template method Patterns in JavaScript

varBeverage=function(param) {varBoilwater=function() {Console.log (' Boil the water ');    }; varbrew=param.brew| |function(){        Throw NewError (' must pass the Brew method ');    }; varpourincup=param.pourincup| |function(){        Throw NewError (' must pass Pourincup method '));    }; varaddcondiments=param.addcondiments| |function(){        Throw NewError (' must pass Addcondiments method '));    }; varf=function(){}; F.prototype.init=function() {boilwater ();        Brew ();        Pourincup ();    Addcondiments ();    }; returnF;};varCoffee=Beverage ({brew:function() {Console.log (' Brew coffee with boiling water '); }, Pourincup:function() {Console.log (' Pour the coffee into the cup '); }, Addcondiments:function() {Console.log (' Add sugar and milk '); }    });varTea=Beverage ({brew:function() {Console.log (' Soak tea with boiling water '); }, Pourincup:function() {Console.log (' Pour the tea into the cup '); }, Addcondiments:function() {Console.log (' Add lemon '); }    });varCoffee=NewCoffee (); Coffee.init ();varTea=NewTea (); Tea.init ();

"JavaScript design pattern and Development practice" the template method pattern of reading notes