Prefer utilizing Null over Undefined

Question

Prefer utilizing Null over Undefined

In my Angular 7 application, I have defined the following interface:

export interface Request {
  limit?: number;
  offset?: number;
}

Additionally, there is a service method implemented like so:

public get(request: Request): Observable<Response>> {

  const parameters = { 'limit': String(request.limit), 'offset': String(request.offset) };

  return this.httpClient.get<Response>>(`projects`, { params: parameters });

}

When calling the service from a component, I have the following snippet:

let request: Request = { offset: 20 };

projectService.get(request)

However, the API response shows the error message:

The value 'undefined' is not valid for Limit.

It seems like I need to assign null to the limit property when it is not explicitly provided in the request. How can I ensure that undefined values are automatically set to null instead of remaining undefined?

angular typescript angular6 angular7

Answer 1

Answer №1

const requestData: RequestData = { start: 20, end : null };

Comparing 0, null, and undefined https://i.sstatic.net/yuKXA.jpg

Answer 2

const requestData: RequestData = { start: 20, end : null };

Comparing 0, null, and undefined https://i.sstatic.net/yuKXA.jpg

Answer 3

Answer №2

When dealing with optional parameters like limit and offset, there are three possibilities to consider:

?limit=undefined&offset=20 insert your code here

For the service:

public get(request: Request): Observable<Response>> {
  const parameters = { 'limit': String(request.limit), 'offset': String(request.offset) };
  return this.httpClient.get<Response>>(`projects`, { params: parameters });
}

Usage example:

let request: Request = { offset: 20 };
projectService.get(request);

?offset=20

For the service:

public get(request: Request): Observable<Response>> {
  const parameters = {};
  if (request.limit) parameters.limit = String(request.limit);
  if (request.offset) parameters.offset = String(request.offset);
  return this.httpClient.get<Response>>(`projects`, { params: parameters });
}

Usage example:

let request: Request = { offset: 20 };
projectService.get(request);

?limit=null&offset=20

For the service:

public get(request: Request): Observable<Response>> {
  const parameters = { 'limit': request.limit ? String(request.limit) : 'null', 'offset': request.offset ? String(request.offset) : 'null' };
  return this.httpClient.get<Response>>(`projects`, { params: parameters });
}

Usage example:

let request: Request = { offset: 20 };
projectService.get(request);

Follow the API's requirements for usage.

Answer 4

When dealing with optional parameters like limit and offset, there are three possibilities to consider:

?limit=undefined&offset=20 insert your code here

For the service:

public get(request: Request): Observable<Response>> {
  const parameters = { 'limit': String(request.limit), 'offset': String(request.offset) };
  return this.httpClient.get<Response>>(`projects`, { params: parameters });
}

Usage example:

let request: Request = { offset: 20 };
projectService.get(request);

?offset=20

For the service:

public get(request: Request): Observable<Response>> {
  const parameters = {};
  if (request.limit) parameters.limit = String(request.limit);
  if (request.offset) parameters.offset = String(request.offset);
  return this.httpClient.get<Response>>(`projects`, { params: parameters });
}

Usage example:

let request: Request = { offset: 20 };
projectService.get(request);

?limit=null&offset=20

For the service:

public get(request: Request): Observable<Response>> {
  const parameters = { 'limit': request.limit ? String(request.limit) : 'null', 'offset': request.offset ? String(request.offset) : 'null' };
  return this.httpClient.get<Response>>(`projects`, { params: parameters });
}

Usage example:

let request: Request = { offset: 20 };
projectService.get(request);

Follow the API's requirements for usage.

Answer 5

Answer №3

Many APIs require the limit parameter to be specified in order to return the exact number of requested items. However, if you believe that this API can handle a null value for the limit, you can utilize the ternary operator to verify the value of request.limit. If the value is not undefined, then convert it to a string using String(request.limit), otherwise set the limit to null. The same approach can be applied to the offset parameter as well.

public fetch(request: Request): Observable<Response>> {

  const params = { 'limit': request.limit ? String(request.limit) : null, 'offset': request.offset ? String(request.offset) : null };

  return this.httpClient.get<Response>>(`projects`, { params: params });

}

Answer 6

Many APIs require the limit parameter to be specified in order to return the exact number of requested items. However, if you believe that this API can handle a null value for the limit, you can utilize the ternary operator to verify the value of request.limit. If the value is not undefined, then convert it to a string using String(request.limit), otherwise set the limit to null. The same approach can be applied to the offset parameter as well.

public fetch(request: Request): Observable<Response>> {

  const params = { 'limit': request.limit ? String(request.limit) : null, 'offset': request.offset ? String(request.offset) : null };

  return this.httpClient.get<Response>>(`projects`, { params: params });

}

Answer 7

Answer №4

How do you feel about this?

let userInput = { 'maximum': userInput.maximum && typeof userInput.maximum === "number" ? String(userInput.maximum) : null, 
                 'minimum': userInput.minimum && typeof userInput.minimum === "number" ? String(userInput.minimum) : null };

Answer 8

How do you feel about this?

let userInput = { 'maximum': userInput.maximum && typeof userInput.maximum === "number" ? String(userInput.maximum) : null, 
                 'minimum': userInput.minimum && typeof userInput.minimum === "number" ? String(userInput.minimum) : null };

Prefer utilizing Null over Undefined

Answer №1

Answer №2

Answer №3

Answer №4

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