I want to create a setter in JS. But there is something wrong with my code, and this is my code:
class test {
constructor(str) {
this.name = str;
}
set name(str) {
this.sayHi();
}
sayHi() {
let temp = this.name;
console.log(`My name is ${temp}`)
}
}
let a = new test('bill') //My name is undefined
a.sayHi() //My name is undefinedwhy does it console undefined in this example?how to make it work?
Your setter needs to store the value somewhere; you'll also need a getter to get the value from that place.
Here's a simple example storing the value in another property:
class Test {
constructor(str) {
this._name = str; // ***
// (You might use `this.name = str` here, setters are sometimes
// considered an exception to the "don't call methods in the
// constructor" rule)
}
set name(str) {
this._name = str; // ***
}
get name() { // ***
return this._name; // ***
} // ***
sayHi() {
let temp = this.name;
console.log(`My name is ${temp}`)
}
}
let a = new Test('bill') //My name is undefined
a.sayHi() //My name is undefinedOf course, if you're going to do that, it doesn't make a lot of sense to have a setter, but that's getting a bit afield of the question...
Note: I changed the name of your class to Test (instead of test). The overwhelming convention in JavaScript is that class names (really constructor function names) are initially-capitalized.
Try this instead:
class test {
constructor(str) {
this.name = str;
}
set name(str) {
this._name = str
}
sayHi() {
let temp = this.name;
console.log(`My name is ${temp}`)
}
get name() {
return this._name
}
}
console.log('My name is ' + this.name)