[英]Can I assign a variable as value to an object's key?
Is this allowed?这是允许的吗?
export class H{
passwordErrorMessage = 'Password must contain 1 small-case alphabet, 1 capital alphabet, 1 digit, 1 special character. The length should be 6-10 characters.'
...
validatePassword(control: FormControl) {
...
return (REG_EXP.test(password)) ? null : {
validatePassword: { // check the class ShowErrorsComponent to see how validatePassword is used.
valid: false,
message: this.passwordErrorMessage //can I do this?
}
};
}
}
For one of my test cases, I am getting the following error对于我的一个测试用例,我收到以下错误
TypeError: Cannot read property 'passwordErrorMessage' of undefined
Error object: Property name: ngDebugContext, value: [object Object]
Error object: Property name: ngErrorLogger, value: function () { [native code] }
TypeError: Cannot read property 'passwordErrorMessage' of undefined
at HelperService.validatePassword (webpack:///./src/app/helper.service.ts?:224:31)
It seems this
is undefined
.似乎this
是undefined
。 I am still in early stages of debugging but my first doubt is if the usage of this
is correct?我仍然在调试初期阶段,但我的第一个疑问是,如果的使用this
是正确的? Things work fine if I change the usage to message: 'Password must contain 1 small-case alphabet, 1 capital alphabet, 1 digit, 1 special character. The length should be 6-10 characters.'
如果我将用法更改为message: 'Password must contain 1 small-case alphabet, 1 capital alphabet, 1 digit, 1 special character. The length should be 6-10 characters.'
则一切正常message: 'Password must contain 1 small-case alphabet, 1 capital alphabet, 1 digit, 1 special character. The length should be 6-10 characters.'
message: 'Password must contain 1 small-case alphabet, 1 capital alphabet, 1 digit, 1 special character. The length should be 6-10 characters.'
yes you can, but you'll need to either bind validatePassword
to the class or use an arrow function to pass this
context into the function.是的,您可以,但您需要将validatePassword
绑定到类或使用箭头函数this
上下文传递到函数中。 this should work:这应该有效:
export class H{
passwordErrorMessage = 'Password must contain 1 small-case alphabet, 1 capital alphabet, 1 digit, 1 special character. The length should be 6-10 characters.'
...
validatePassword = (control: FormControl) => {
...
return (REG_EXP.test(password)) ? null : {
validatePassword: { // check the class ShowErrorsComponent to see how validatePassword is used.
valid: false,
message: this.passwordErrorMessage
}
};
}
}
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