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I have never used Javascript's setter and getter methods before when writing projects, so it is a concept that needs to be understood. Today I saw this knowledge point in a book, but it was still vague, so I planned to Research and study;
The properties of a Javascript object are composed of a name, a value and a set of properties. So first, let’s take a look at the two properties of the object:
Data properties, which we often use, should be familiar with
Accessor properties, also called accessor properties
What are accessor properties? It is a set of functions that get and set values. In ECMAScript5, property values can be set using one or two methods, the two methods are getters and setters; therefore, properties defined by getters and setters are called accessor properties.
var o = { get val(){ /*函数体*/ return ; }, set val(n){ /*函数体*/ } }
The above is the simplest way to define an accessor property. It can be seen that the getter and setter methods actually replace A function of function.
var o = { a:3, get val(){ return Math.pow(this.a,2); } } console.log(o.val);//9 o.val = 100; console.log(o.val);//9
The getter method has no parameters and returns a value; when the getter method is set separately, only the attribute value can be obtained. The defined attribute values cannot be changed, ensuring data security;
var o = { a:3, set val(n){ this.a = n; } } console.log(o.val);//undefined
The setter method has parameters and no return value ; When setting the setter method alone, the attribute value cannot be read;
var o ={ a:3, get val(){ return Math.pow(this.a,n); }, set val(n){ this.a = Math.max(this.a,n); } } console.log(o.a);//3 console.log(o.val);//9 o.val = 10; console.log(o.a);//10 console.log(o.val);//100
As can be seen from the above code, Where this refers to its object (i.e. "o" in the code);
var o ={ a:3, get val(){ return Math.pow(this.a,n); }, set val(n){ this.a = Math.max(this.a,n); } } o.val = 10; var foo = Object.create(o); console.log(foo.val);//10 foo.val = 9; console.log(foo.val);//10
In addition, the accessor attribute can also be inherited.
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Basic introduction to getters and setters in Javascript
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Implemented the code of a PHP5 getter/setter base class_php skills
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