Question

如何从构造函数中访问原型对象？

在下面的Javascript代码中，我有一个Person构造函数，该函数带有两个getter / setter函数，以及在其原型中定义的hydrate函数：

final LOCAL='local'
final DEV='dev'

void configBootTask(Task bootTask, String profile) {
    bootTask.main = bootJar.mainClassName
    bootTask.classpath = sourceSets.main.runtimeClasspath

    bootTask.args = [ "--spring.profiles.active=$profile" ]
//    systemProperty 'spring.profiles.active', profile // this approach also may be used
    bootTask.environment = postgresLocalEnvironment
}

bootRun {
    description "Run Spring boot application with \"$LOCAL\" profile"
    doFirst() {
        configBootTask(it, LOCAL)
    }
}

task bootRunLocal(type: BootRun, dependsOn: 'classes') {
    description "Alias to \":${bootRun.name}\" task: ${bootRun.description}"
    doFirst() {
        configBootTask(it, LOCAL)
    }
}

task bootRunDev(type: BootRun, dependsOn: 'classes') {
    description "Run Spring boot application with \"$DEV\" profile"
    doFirst() {
        configBootTask(it, DEV)
    }
}

task bootPostgresRunLocal(type: BootRun) {
    description "Run Spring boot application with \"$LOCAL\" profile and re-creating DB Postgres container"
    dependsOn runPostgresDocker
    finalizedBy killPostgresDocker
    doFirst() {
        configBootTask(it, LOCAL)
    }
}

task bootPostgresRunDev(type: BootRun) {
    description "Run Spring boot application with \"$DEV\" profile and re-creating DB Postgres container"
    dependsOn runPostgresDocker
    finalizedBy killPostgresDocker
    doFirst() {
        configBootTask(it, DEV)
    }
}

我想从Person构造函数中调用hydrate（）函数，即使这对我来说没有意义，就像在完全创建对象之前调用方法，对吗？如果我错了纠正我。 JavaScript代码：

+++++++++++++++++++++++++++++
+          Person           +
+++++++++++++++++++++++++++++
+ setFirstname( firstname ) +
+ getFirstname()            +
+ setLastname( lastname )   +
+ getLastname()             +
+++++++++++++++++++++++++++++

+++++++++++++++++++++++++++++
+     Person.prototype      +
+++++++++++++++++++++++++++++
+ hydrate( person )         +
+++++++++++++++++++++++++++++

结果：

错误：未捕获的TypeError：this.setFirstname不是函数

问题：我该怎么做？那有可能吗？

Answer 1

为此，我应该更改了hydrate（）函数的调用位置，并将其置于底部[在setFirstname（）和setLastname（）公开可用之后），如下所示：

function Person( person ) {
    var _firstname = '',
        _lastname ='';


    function setFirstname( firstname ) {
        _firstname = firstname;
    }

    function getFirstname() {
        return _firstname;
    }

    function setLastname( lastname ) {
        _lastname = lastname;
    }

    function getLastname() {
        return _lastname;
    }

    this.setFirstname = setFirstname;
    this.getFirstname = getFirstname;

    this.setLastname = setLastname;
    this.getLastname = getLastname;

    if ( person ) this.hydrate( person );

}

Person.prototype = {

    hydrate: function( person ) {
        this.setFirstname( person.firstname );
        this.setLastname( person.lastname );
    }

};


var john = new Person( {
    firstname: "John",
    lastname: "Doe"
} );

如何从构造函数中访问原型对象？

1 个答案: