What are the counterparts of HasValue and .Value in TypeScript?

Question

What are the counterparts of HasValue and .Value in TypeScript?

There is a method in my code:

public cancelOperation(OperationId: string): Promise<void> 
 {
         // some calls
 }

I retrieve OperationId from another function:

let operationId = GetOperationId() {}

which returns a nullable OperationId,

 operationId?: string;

When trying to use the OperationId received from GetOperationId() in the cancelOperation() method, I encounter an error due to its nullable nature.

Is there an equivalent of

 operationId .Value

or

operationId .HasValue

function in Typescript that I can utilize?

Even though I could handle it by checking the value of operationId like this:

 cancelOperation(playAudioResult.operationId ? playAudioResult.operationId : "")

I'm looking for a solution that would allow me to do something similar to:

cancelOperation(operationId.?????)

javascript c#typescript conditional-operator null-check

Answer 1

Answer №1

When working in TypeScript, using <code>if (operationId)

allows you to check for null values. This conditional statement will evaluate to true if operationId is defined and not null or undefined.

Answer 2

When working in TypeScript, using <code>if (operationId)

allows you to check for null values. This conditional statement will evaluate to true if operationId is defined and not null or undefined.

Answer 3

Answer №2

To determine if operationI is null, you can use the "if" statement or the nullish coalescing operator.

The nullish coalescing operator returns the right-hand side operand if the left-hand side operand is null or undefined.

It will only execute if the value is not null, like in the example code snippet below:

let x = operationI ?? NULL

Answer 4

To determine if operationI is null, you can use the "if" statement or the nullish coalescing operator.

The nullish coalescing operator returns the right-hand side operand if the left-hand side operand is null or undefined.

It will only execute if the value is not null, like in the example code snippet below:

let x = operationI ?? NULL

Answer 5

Answer №3

After reading the article recommended by @ShamPooSham https://www.typescriptlang.org/docs/handbook/release-notes/typescript-2-0.html#non-null-assertion-operator

I discovered a method to retrieve value from a nullable property as outlined in the article.

To do this, we simply add ! after the property and access the value (assuming it's not null).

// Compiled with --strictNullChecks
function validateEntity(e?: Entity) {
  // Throw exception if e is null or invalid entity
}
function processEntity(e?: Entity) {
 validateEntity(e);
 let s = e!.name; // Ensure that e is non-null and access name
}

In a similar way, I can use the following in my method:

cancelOperation(playAudioResult.operationId!)  // note the !

Answer 6

After reading the article recommended by @ShamPooSham https://www.typescriptlang.org/docs/handbook/release-notes/typescript-2-0.html#non-null-assertion-operator

I discovered a method to retrieve value from a nullable property as outlined in the article.

To do this, we simply add ! after the property and access the value (assuming it's not null).

// Compiled with --strictNullChecks
function validateEntity(e?: Entity) {
  // Throw exception if e is null or invalid entity
}
function processEntity(e?: Entity) {
 validateEntity(e);
 let s = e!.name; // Ensure that e is non-null and access name
}

In a similar way, I can use the following in my method:

cancelOperation(playAudioResult.operationId!)  // note the !

What are the counterparts of HasValue and .Value in TypeScript?

Answer №1

Answer №2

Answer №3

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