Angular 7 - Dynamic Forms and passing a function through












0














Using Angular's Dynamic forms I'm building a new input field



form.ts



 usernameCallback(body) {
console.log(`hello ${body}`);
this.usernameService.post(body)
.subscribe(
data => {
console.log(data);
},
error => {
console.warn(`Error: ${error}`);
}
);
}

ngOnInit() {

new InputField({
key: 'username',
label: 'Username',
value: '',
placeholder: 'Enter username',
required: true,
callback: this.usernameCallback
}),

}


So this is the basics of the code.



I have inside UsernameService a method post() which sends an http post request.



usernameCallback() is added to the InputField and has the type of Function to it.



Within input.component.ts where the form is built I am doing



  callback() {
console.log(this.field.callback);
this.field.callback('cheddar');
}


The console log prints out the content from usernameCallback which is fine but I get an error




ERROR TypeError: Cannot read property 'post' of undefined




It looks like it isn't able to process the usernameService but I cannot figure out why.










share|improve this question




















  • 1




    this.usernameCallback.bind(this) should do the trick
    – yurzui
    Nov 22 at 18:01










  • Alternatively you can use instance arrow function like usernameCallback = (body) => { More on this you can find everywhere:) github.com/Microsoft/TypeScript/wiki/%27this%27-in-TypeScript
    – yurzui
    Nov 22 at 18:03












  • Where should this.usernameCallback.bind(this) be places @yurzui
    – ngDough
    Nov 22 at 18:07










  • callback: this.usernameCallback.bind(this)
    – yurzui
    Nov 22 at 18:18










  • Possible duplicate of How to access the correct `this` inside a callback?
    – ConnorsFan
    Nov 22 at 18:49
















0














Using Angular's Dynamic forms I'm building a new input field



form.ts



 usernameCallback(body) {
console.log(`hello ${body}`);
this.usernameService.post(body)
.subscribe(
data => {
console.log(data);
},
error => {
console.warn(`Error: ${error}`);
}
);
}

ngOnInit() {

new InputField({
key: 'username',
label: 'Username',
value: '',
placeholder: 'Enter username',
required: true,
callback: this.usernameCallback
}),

}


So this is the basics of the code.



I have inside UsernameService a method post() which sends an http post request.



usernameCallback() is added to the InputField and has the type of Function to it.



Within input.component.ts where the form is built I am doing



  callback() {
console.log(this.field.callback);
this.field.callback('cheddar');
}


The console log prints out the content from usernameCallback which is fine but I get an error




ERROR TypeError: Cannot read property 'post' of undefined




It looks like it isn't able to process the usernameService but I cannot figure out why.










share|improve this question




















  • 1




    this.usernameCallback.bind(this) should do the trick
    – yurzui
    Nov 22 at 18:01










  • Alternatively you can use instance arrow function like usernameCallback = (body) => { More on this you can find everywhere:) github.com/Microsoft/TypeScript/wiki/%27this%27-in-TypeScript
    – yurzui
    Nov 22 at 18:03












  • Where should this.usernameCallback.bind(this) be places @yurzui
    – ngDough
    Nov 22 at 18:07










  • callback: this.usernameCallback.bind(this)
    – yurzui
    Nov 22 at 18:18










  • Possible duplicate of How to access the correct `this` inside a callback?
    – ConnorsFan
    Nov 22 at 18:49














0












0








0







Using Angular's Dynamic forms I'm building a new input field



form.ts



 usernameCallback(body) {
console.log(`hello ${body}`);
this.usernameService.post(body)
.subscribe(
data => {
console.log(data);
},
error => {
console.warn(`Error: ${error}`);
}
);
}

ngOnInit() {

new InputField({
key: 'username',
label: 'Username',
value: '',
placeholder: 'Enter username',
required: true,
callback: this.usernameCallback
}),

}


So this is the basics of the code.



I have inside UsernameService a method post() which sends an http post request.



usernameCallback() is added to the InputField and has the type of Function to it.



Within input.component.ts where the form is built I am doing



  callback() {
console.log(this.field.callback);
this.field.callback('cheddar');
}


The console log prints out the content from usernameCallback which is fine but I get an error




ERROR TypeError: Cannot read property 'post' of undefined




It looks like it isn't able to process the usernameService but I cannot figure out why.










share|improve this question















Using Angular's Dynamic forms I'm building a new input field



form.ts



 usernameCallback(body) {
console.log(`hello ${body}`);
this.usernameService.post(body)
.subscribe(
data => {
console.log(data);
},
error => {
console.warn(`Error: ${error}`);
}
);
}

ngOnInit() {

new InputField({
key: 'username',
label: 'Username',
value: '',
placeholder: 'Enter username',
required: true,
callback: this.usernameCallback
}),

}


So this is the basics of the code.



I have inside UsernameService a method post() which sends an http post request.



usernameCallback() is added to the InputField and has the type of Function to it.



Within input.component.ts where the form is built I am doing



  callback() {
console.log(this.field.callback);
this.field.callback('cheddar');
}


The console log prints out the content from usernameCallback which is fine but I get an error




ERROR TypeError: Cannot read property 'post' of undefined




It looks like it isn't able to process the usernameService but I cannot figure out why.







angular angular7






share|improve this question















share|improve this question













share|improve this question




share|improve this question








edited Nov 29 at 17:03









Goncalo Peres

1,3261318




1,3261318










asked Nov 22 at 18:00









ngDough

607




607








  • 1




    this.usernameCallback.bind(this) should do the trick
    – yurzui
    Nov 22 at 18:01










  • Alternatively you can use instance arrow function like usernameCallback = (body) => { More on this you can find everywhere:) github.com/Microsoft/TypeScript/wiki/%27this%27-in-TypeScript
    – yurzui
    Nov 22 at 18:03












  • Where should this.usernameCallback.bind(this) be places @yurzui
    – ngDough
    Nov 22 at 18:07










  • callback: this.usernameCallback.bind(this)
    – yurzui
    Nov 22 at 18:18










  • Possible duplicate of How to access the correct `this` inside a callback?
    – ConnorsFan
    Nov 22 at 18:49














  • 1




    this.usernameCallback.bind(this) should do the trick
    – yurzui
    Nov 22 at 18:01










  • Alternatively you can use instance arrow function like usernameCallback = (body) => { More on this you can find everywhere:) github.com/Microsoft/TypeScript/wiki/%27this%27-in-TypeScript
    – yurzui
    Nov 22 at 18:03












  • Where should this.usernameCallback.bind(this) be places @yurzui
    – ngDough
    Nov 22 at 18:07










  • callback: this.usernameCallback.bind(this)
    – yurzui
    Nov 22 at 18:18










  • Possible duplicate of How to access the correct `this` inside a callback?
    – ConnorsFan
    Nov 22 at 18:49








1




1




this.usernameCallback.bind(this) should do the trick
– yurzui
Nov 22 at 18:01




this.usernameCallback.bind(this) should do the trick
– yurzui
Nov 22 at 18:01












Alternatively you can use instance arrow function like usernameCallback = (body) => { More on this you can find everywhere:) github.com/Microsoft/TypeScript/wiki/%27this%27-in-TypeScript
– yurzui
Nov 22 at 18:03






Alternatively you can use instance arrow function like usernameCallback = (body) => { More on this you can find everywhere:) github.com/Microsoft/TypeScript/wiki/%27this%27-in-TypeScript
– yurzui
Nov 22 at 18:03














Where should this.usernameCallback.bind(this) be places @yurzui
– ngDough
Nov 22 at 18:07




Where should this.usernameCallback.bind(this) be places @yurzui
– ngDough
Nov 22 at 18:07












callback: this.usernameCallback.bind(this)
– yurzui
Nov 22 at 18:18




callback: this.usernameCallback.bind(this)
– yurzui
Nov 22 at 18:18












Possible duplicate of How to access the correct `this` inside a callback?
– ConnorsFan
Nov 22 at 18:49




Possible duplicate of How to access the correct `this` inside a callback?
– ConnorsFan
Nov 22 at 18:49

















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