Set variable from function

This may be an easy question/answer, but I can't seem to wrap my head around it:
I am validating fields with a function using AbstractControl:

errorVar: boolean = false

function(c: AbstractControl): [key: string]: string | null 
 // validation if 'test' is true or not goes here
 if(test) 
 let errorMessageText: "test"
 return 'errorText': errorMessageText;
 
return null;

Besides the errorText I want the function to also set the variable errorVar to true and to false if the function returns null.

edited Nov 14 '18 at 10:48

asked Nov 14 '18 at 9:14

PhilipK

237

And what is your problem?

– Daniel Hilgarth
Nov 14 '18 at 9:15

If I try to set the variable inside the function it comes back as "undefined is not an object. So I'm fairly new to this and can't figure out why. So my idea was to have the function return the variable

– PhilipK
Nov 14 '18 at 10:47

add a comment |

This may be an easy question/answer, but I can't seem to wrap my head around it:
I am validating fields with a function using AbstractControl:

errorVar: boolean = false

function(c: AbstractControl): [key: string]: string | null 
 // validation if 'test' is true or not goes here
 if(test) 
 let errorMessageText: "test"
 return 'errorText': errorMessageText;
 
return null;

Besides the errorText I want the function to also set the variable errorVar to true and to false if the function returns null.

edited Nov 14 '18 at 10:48

asked Nov 14 '18 at 9:14

PhilipK

237

And what is your problem?

– Daniel Hilgarth
Nov 14 '18 at 9:15

If I try to set the variable inside the function it comes back as "undefined is not an object. So I'm fairly new to this and can't figure out why. So my idea was to have the function return the variable

– PhilipK
Nov 14 '18 at 10:47

add a comment |

This may be an easy question/answer, but I can't seem to wrap my head around it:
I am validating fields with a function using AbstractControl:

errorVar: boolean = false

function(c: AbstractControl): [key: string]: string | null 
 // validation if 'test' is true or not goes here
 if(test) 
 let errorMessageText: "test"
 return 'errorText': errorMessageText;
 
return null;

Besides the errorText I want the function to also set the variable errorVar to true and to false if the function returns null.

edited Nov 14 '18 at 10:48

asked Nov 14 '18 at 9:14

PhilipK

237

This may be an easy question/answer, but I can't seem to wrap my head around it:
I am validating fields with a function using AbstractControl:

errorVar: boolean = false

function(c: AbstractControl): [key: string]: string | null 
 // validation if 'test' is true or not goes here
 if(test) 
 let errorMessageText: "test"
 return 'errorText': errorMessageText;
 
return null;

Besides the errorText I want the function to also set the variable errorVar to true and to false if the function returns null.

angular typescript

edited Nov 14 '18 at 10:48

asked Nov 14 '18 at 9:14

PhilipK

237

edited Nov 14 '18 at 10:48

asked Nov 14 '18 at 9:14

PhilipK

237

edited Nov 14 '18 at 10:48

asked Nov 14 '18 at 9:14

PhilipK

237

asked Nov 14 '18 at 9:14

PhilipK

237

asked Nov 14 '18 at 9:14

PhilipK

237

And what is your problem?

– Daniel Hilgarth
Nov 14 '18 at 9:15

If I try to set the variable inside the function it comes back as "undefined is not an object. So I'm fairly new to this and can't figure out why. So my idea was to have the function return the variable

– PhilipK
Nov 14 '18 at 10:47

add a comment |

And what is your problem?

– Daniel Hilgarth
Nov 14 '18 at 9:15

If I try to set the variable inside the function it comes back as "undefined is not an object. So I'm fairly new to this and can't figure out why. So my idea was to have the function return the variable

– PhilipK
Nov 14 '18 at 10:47

And what is your problem?

– Daniel Hilgarth
Nov 14 '18 at 9:15

If I try to set the variable inside the function it comes back as "undefined is not an object. So I'm fairly new to this and can't figure out why. So my idea was to have the function return the variable

– PhilipK
Nov 14 '18 at 10:47

add a comment |

2 Answers
2

active

oldest

votes

You can do something like this:

 errorVar: boolean = false

 function(c: AbstractControl): [key: string]: string | null 
 // validation if 'test' is true or not goes here
 if (test) 
 this.errorVar = true;
 let errorMessageText:
 return 'errorText': errorMessageText ;
 

 this.errorVar = false;
 return null;

edited Nov 14 '18 at 9:25

Oram

802417

answered Nov 14 '18 at 9:19

Hayden Hall

24135

Nope, tried that first of course. It comes back "undefined is not an object"

– PhilipK
Nov 14 '18 at 10:39

Is errorVar defined within the context of a class?

– Hayden Hall
Nov 14 '18 at 10:48

yes, it is - it's a reactive form and the variable definition and function is inside the export class

– PhilipK
Nov 14 '18 at 10:52

add a comment |

I think there are several problems

your errorVar should be declared using var or let so you can set it in the function via a closure

your errorMessageText variable must be set using = and not :

like this:

var errorVar: boolean = false;

function(c: AbstractControl): [key: string]: string | null 
 // validation if 'test' is true or not goes here
 if(test) 
 errorVar = true;
 let errorMessageText: string ="test";
 return 'errorText': errorMessageText;
 
 errorVar = false;
 return null;

answered Nov 14 '18 at 13:12

XouDo

6916

Thanks for your answer, but that's not why it's not working. The errorVar: boolean = false was meant as a pointer that I have declared the variable earlier in the class; the function is a representation what I want to achieve, not a functioning piece of code. Not that I can explain it, but rest assured, I have about 20 other declarations that work just fine this way. ...and to your second point, TypeScript let's you define the variable type by using a colon after the name.

– PhilipK
Nov 15 '18 at 8:08

Well, I tested my code on TypeScript playground. let errorMessageText: "test" did not work (errorMessageTextwas undefined), but let errorMessageText= "test" did.

– XouDo
Nov 15 '18 at 9:12

Concerning the "pointer" thing, what you can do is pass an object errorMessageText:"" as parameter, and modify its property inside the function.

– XouDo
Nov 15 '18 at 9:22

Of course it didn't, because as I said before, you define the type of the variable with the colon ":" and write it with the equal sign "=". So in this example I am setting errorMessageText as type string.... but all that is beside the point, because the function properly returns errorMessageText, what I need is that the function returns a SECOND variable!

– PhilipK
Nov 17 '18 at 10:28

Ok, this was a typo error. Could it be that you have a problem of this binding that prevents you from settings errorVar (if it's declared in a class)? In that case, you could bind explicitly by passing myFunction.bind(myInstance) instead of myFunction. Anyway, good luck for your problem.

– XouDo
Nov 18 '18 at 6:36

add a comment |

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2 Answers
2

active

oldest

votes

2 Answers
2

active

oldest

votes

You can do something like this:

 errorVar: boolean = false

 function(c: AbstractControl): [key: string]: string | null 
 // validation if 'test' is true or not goes here
 if (test) 
 this.errorVar = true;
 let errorMessageText:
 return 'errorText': errorMessageText ;
 

 this.errorVar = false;
 return null;

edited Nov 14 '18 at 9:25

Oram

802417

answered Nov 14 '18 at 9:19

Hayden Hall

24135

Nope, tried that first of course. It comes back "undefined is not an object"

– PhilipK
Nov 14 '18 at 10:39

Is errorVar defined within the context of a class?

– Hayden Hall
Nov 14 '18 at 10:48

yes, it is - it's a reactive form and the variable definition and function is inside the export class

– PhilipK
Nov 14 '18 at 10:52

add a comment |

You can do something like this:

 errorVar: boolean = false

 function(c: AbstractControl): [key: string]: string | null 
 // validation if 'test' is true or not goes here
 if (test) 
 this.errorVar = true;
 let errorMessageText:
 return 'errorText': errorMessageText ;
 

 this.errorVar = false;
 return null;

edited Nov 14 '18 at 9:25

Oram

802417

answered Nov 14 '18 at 9:19

Hayden Hall

24135

Nope, tried that first of course. It comes back "undefined is not an object"

– PhilipK
Nov 14 '18 at 10:39

Is errorVar defined within the context of a class?

– Hayden Hall
Nov 14 '18 at 10:48

yes, it is - it's a reactive form and the variable definition and function is inside the export class

– PhilipK
Nov 14 '18 at 10:52

add a comment |

You can do something like this:

 errorVar: boolean = false

 function(c: AbstractControl): [key: string]: string | null 
 // validation if 'test' is true or not goes here
 if (test) 
 this.errorVar = true;
 let errorMessageText:
 return 'errorText': errorMessageText ;
 

 this.errorVar = false;
 return null;

edited Nov 14 '18 at 9:25

Oram

802417

answered Nov 14 '18 at 9:19

Hayden Hall

24135

You can do something like this:

 errorVar: boolean = false

 function(c: AbstractControl): [key: string]: string | null 
 // validation if 'test' is true or not goes here
 if (test) 
 this.errorVar = true;
 let errorMessageText:
 return 'errorText': errorMessageText ;
 

 this.errorVar = false;
 return null;

edited Nov 14 '18 at 9:25

Oram

802417

answered Nov 14 '18 at 9:19

Hayden Hall

24135

edited Nov 14 '18 at 9:25

Oram

802417

edited Nov 14 '18 at 9:25

Oram

802417

edited Nov 14 '18 at 9:25

Oram

802417

answered Nov 14 '18 at 9:19

Hayden Hall

24135

answered Nov 14 '18 at 9:19

Hayden Hall

24135

answered Nov 14 '18 at 9:19

Hayden Hall

24135

Nope, tried that first of course. It comes back "undefined is not an object"

– PhilipK
Nov 14 '18 at 10:39

Is errorVar defined within the context of a class?

– Hayden Hall
Nov 14 '18 at 10:48

yes, it is - it's a reactive form and the variable definition and function is inside the export class

– PhilipK
Nov 14 '18 at 10:52

add a comment |

Nope, tried that first of course. It comes back "undefined is not an object"

– PhilipK
Nov 14 '18 at 10:39

Is errorVar defined within the context of a class?

– Hayden Hall
Nov 14 '18 at 10:48

yes, it is - it's a reactive form and the variable definition and function is inside the export class

– PhilipK
Nov 14 '18 at 10:52

Nope, tried that first of course. It comes back "undefined is not an object"

– PhilipK
Nov 14 '18 at 10:39

Is errorVar defined within the context of a class?

– Hayden Hall
Nov 14 '18 at 10:48

yes, it is - it's a reactive form and the variable definition and function is inside the export class

– PhilipK
Nov 14 '18 at 10:52

add a comment |

I think there are several problems

your errorVar should be declared using var or let so you can set it in the function via a closure

your errorMessageText variable must be set using = and not :

like this:

var errorVar: boolean = false;

function(c: AbstractControl): [key: string]: string | null 
 // validation if 'test' is true or not goes here
 if(test) 
 errorVar = true;
 let errorMessageText: string ="test";
 return 'errorText': errorMessageText;
 
 errorVar = false;
 return null;

answered Nov 14 '18 at 13:12

XouDo

6916

Thanks for your answer, but that's not why it's not working. The errorVar: boolean = false was meant as a pointer that I have declared the variable earlier in the class; the function is a representation what I want to achieve, not a functioning piece of code. Not that I can explain it, but rest assured, I have about 20 other declarations that work just fine this way. ...and to your second point, TypeScript let's you define the variable type by using a colon after the name.

– PhilipK
Nov 15 '18 at 8:08

Well, I tested my code on TypeScript playground. let errorMessageText: "test" did not work (errorMessageTextwas undefined), but let errorMessageText= "test" did.

– XouDo
Nov 15 '18 at 9:12

Concerning the "pointer" thing, what you can do is pass an object errorMessageText:"" as parameter, and modify its property inside the function.

– XouDo
Nov 15 '18 at 9:22

Of course it didn't, because as I said before, you define the type of the variable with the colon ":" and write it with the equal sign "=". So in this example I am setting errorMessageText as type string.... but all that is beside the point, because the function properly returns errorMessageText, what I need is that the function returns a SECOND variable!

– PhilipK
Nov 17 '18 at 10:28

Ok, this was a typo error. Could it be that you have a problem of this binding that prevents you from settings errorVar (if it's declared in a class)? In that case, you could bind explicitly by passing myFunction.bind(myInstance) instead of myFunction. Anyway, good luck for your problem.

– XouDo
Nov 18 '18 at 6:36

add a comment |

I think there are several problems

your errorVar should be declared using var or let so you can set it in the function via a closure

your errorMessageText variable must be set using = and not :

like this:

var errorVar: boolean = false;

function(c: AbstractControl): [key: string]: string | null 
 // validation if 'test' is true or not goes here
 if(test) 
 errorVar = true;
 let errorMessageText: string ="test";
 return 'errorText': errorMessageText;
 
 errorVar = false;
 return null;

answered Nov 14 '18 at 13:12

XouDo

6916

Thanks for your answer, but that's not why it's not working. The errorVar: boolean = false was meant as a pointer that I have declared the variable earlier in the class; the function is a representation what I want to achieve, not a functioning piece of code. Not that I can explain it, but rest assured, I have about 20 other declarations that work just fine this way. ...and to your second point, TypeScript let's you define the variable type by using a colon after the name.

– PhilipK
Nov 15 '18 at 8:08

Well, I tested my code on TypeScript playground. let errorMessageText: "test" did not work (errorMessageTextwas undefined), but let errorMessageText= "test" did.

– XouDo
Nov 15 '18 at 9:12

Concerning the "pointer" thing, what you can do is pass an object errorMessageText:"" as parameter, and modify its property inside the function.

– XouDo
Nov 15 '18 at 9:22

Of course it didn't, because as I said before, you define the type of the variable with the colon ":" and write it with the equal sign "=". So in this example I am setting errorMessageText as type string.... but all that is beside the point, because the function properly returns errorMessageText, what I need is that the function returns a SECOND variable!

– PhilipK
Nov 17 '18 at 10:28

Ok, this was a typo error. Could it be that you have a problem of this binding that prevents you from settings errorVar (if it's declared in a class)? In that case, you could bind explicitly by passing myFunction.bind(myInstance) instead of myFunction. Anyway, good luck for your problem.

– XouDo
Nov 18 '18 at 6:36

add a comment |

I think there are several problems

your errorVar should be declared using var or let so you can set it in the function via a closure

your errorMessageText variable must be set using = and not :

like this:

var errorVar: boolean = false;

function(c: AbstractControl): [key: string]: string | null 
 // validation if 'test' is true or not goes here
 if(test) 
 errorVar = true;
 let errorMessageText: string ="test";
 return 'errorText': errorMessageText;
 
 errorVar = false;
 return null;

answered Nov 14 '18 at 13:12

XouDo

6916

I think there are several problems

your errorVar should be declared using var or let so you can set it in the function via a closure

your errorMessageText variable must be set using = and not :

like this:

var errorVar: boolean = false;

function(c: AbstractControl): [key: string]: string | null 
 // validation if 'test' is true or not goes here
 if(test) 
 errorVar = true;
 let errorMessageText: string ="test";
 return 'errorText': errorMessageText;
 
 errorVar = false;
 return null;

answered Nov 14 '18 at 13:12

XouDo

6916

answered Nov 14 '18 at 13:12

XouDo

6916

answered Nov 14 '18 at 13:12

XouDo

6916

answered Nov 14 '18 at 13:12

XouDo

6916

Thanks for your answer, but that's not why it's not working. The errorVar: boolean = false was meant as a pointer that I have declared the variable earlier in the class; the function is a representation what I want to achieve, not a functioning piece of code. Not that I can explain it, but rest assured, I have about 20 other declarations that work just fine this way. ...and to your second point, TypeScript let's you define the variable type by using a colon after the name.

– PhilipK
Nov 15 '18 at 8:08

Well, I tested my code on TypeScript playground. let errorMessageText: "test" did not work (errorMessageTextwas undefined), but let errorMessageText= "test" did.

– XouDo
Nov 15 '18 at 9:12

Concerning the "pointer" thing, what you can do is pass an object errorMessageText:"" as parameter, and modify its property inside the function.

– XouDo
Nov 15 '18 at 9:22

Of course it didn't, because as I said before, you define the type of the variable with the colon ":" and write it with the equal sign "=". So in this example I am setting errorMessageText as type string.... but all that is beside the point, because the function properly returns errorMessageText, what I need is that the function returns a SECOND variable!

– PhilipK
Nov 17 '18 at 10:28

Ok, this was a typo error. Could it be that you have a problem of this binding that prevents you from settings errorVar (if it's declared in a class)? In that case, you could bind explicitly by passing myFunction.bind(myInstance) instead of myFunction. Anyway, good luck for your problem.

– XouDo
Nov 18 '18 at 6:36

add a comment |

Thanks for your answer, but that's not why it's not working. The errorVar: boolean = false was meant as a pointer that I have declared the variable earlier in the class; the function is a representation what I want to achieve, not a functioning piece of code. Not that I can explain it, but rest assured, I have about 20 other declarations that work just fine this way. ...and to your second point, TypeScript let's you define the variable type by using a colon after the name.

– PhilipK
Nov 15 '18 at 8:08

Well, I tested my code on TypeScript playground. let errorMessageText: "test" did not work (errorMessageTextwas undefined), but let errorMessageText= "test" did.

– XouDo
Nov 15 '18 at 9:12

Concerning the "pointer" thing, what you can do is pass an object errorMessageText:"" as parameter, and modify its property inside the function.

– XouDo
Nov 15 '18 at 9:22

Of course it didn't, because as I said before, you define the type of the variable with the colon ":" and write it with the equal sign "=". So in this example I am setting errorMessageText as type string.... but all that is beside the point, because the function properly returns errorMessageText, what I need is that the function returns a SECOND variable!

– PhilipK
Nov 17 '18 at 10:28

Ok, this was a typo error. Could it be that you have a problem of this binding that prevents you from settings errorVar (if it's declared in a class)? In that case, you could bind explicitly by passing myFunction.bind(myInstance) instead of myFunction. Anyway, good luck for your problem.

– XouDo
Nov 18 '18 at 6:36

Thanks for your answer, but that's not why it's not working. The errorVar: boolean = false was meant as a pointer that I have declared the variable earlier in the class; the function is a representation what I want to achieve, not a functioning piece of code. Not that I can explain it, but rest assured, I have about 20 other declarations that work just fine this way. ...and to your second point, TypeScript let's you define the variable type by using a colon after the name.

– PhilipK
Nov 15 '18 at 8:08

Well, I tested my code on TypeScript playground. let errorMessageText: "test" did not work (errorMessageTextwas undefined), but let errorMessageText= "test" did.

– XouDo
Nov 15 '18 at 9:12

Concerning the "pointer" thing, what you can do is pass an object errorMessageText:"" as parameter, and modify its property inside the function.

– XouDo
Nov 15 '18 at 9:22

Of course it didn't, because as I said before, you define the type of the variable with the colon ":" and write it with the equal sign "=". So in this example I am setting errorMessageText as type string.... but all that is beside the point, because the function properly returns errorMessageText, what I need is that the function returns a SECOND variable!

– PhilipK
Nov 17 '18 at 10:28

Ok, this was a typo error. Could it be that you have a problem of this binding that prevents you from settings errorVar (if it's declared in a class)? In that case, you could bind explicitly by passing myFunction.bind(myInstance) instead of myFunction. Anyway, good luck for your problem.

– XouDo
Nov 18 '18 at 6:36

add a comment |

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