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LazyPromise Class

A lazy evaluated promise. The execute function is delayed until the promise is used, e.g. await, then, catch ... The execute function is only called once. All calls are then proxied to the promise returned by the execute method. \

This API is provided for existing users, but is not recommended for new users.

To use, import via @fluidframework/core-utils/legacy.

For more information about our API support guarantees, see here.

Signature​

export declare class LazyPromise<T> implements Promise<T>

Implements: Promise<T>

Type Parameters​

Parameter Description
T

Constructors​

Constructor Alerts Description
(constructor)(execute) Beta Constructs a new instance of the LazyPromise class

Properties​

Property Alerts Modifiers Type Description
[Symbol.toStringTag] Beta readonly string

Methods​

Method Alerts Return Type Description
catch(onrejected) Beta Promise<T | TResult>
finally(onfinally) Beta Promise<T>
then(onfulfilled, onrejected) Beta Promise<TResult1 | TResult2>

Constructor Details​

(constructor)​

Constructs a new instance of the LazyPromise class

This API is provided for existing users, but is not recommended for new users.

For more information about our API support guarantees, see here.

Signature​
constructor(execute: () => Promise<T>);

Parameters​

Parameter Type Description
execute () => Promise<T>

Property Details​

[Symbol.toStringTag]​

This API is provided for existing users, but is not recommended for new users.

For more information about our API support guarantees, see here.

Signature​
get [Symbol.toStringTag](): string;

Type: string

Method Details​

catch​

This API is provided for existing users, but is not recommended for new users.

For more information about our API support guarantees, see here.

Signature​
catch<TResult = never>(onrejected?: ((reason: any) => TResult | PromiseLike<TResult>) | null | undefined): Promise<T | TResult>;
Type Parameters​
Parameter Default Description
TResult never

Parameters​

Parameter Modifiers Type Description
onrejected optional ((reason: any) => TResult | PromiseLike<TResult>) | null | undefined

Returns​

Return type: Promise<T | TResult>

finally​

This API is provided for existing users, but is not recommended for new users.

For more information about our API support guarantees, see here.

Signature​
finally(onfinally?: (() => void) | null | undefined): Promise<T>;

Parameters​

Parameter Modifiers Type Description
onfinally optional (() => void) | null | undefined

Returns​

Return type: Promise<T>

then​

This API is provided for existing users, but is not recommended for new users.

For more information about our API support guarantees, see here.

Signature​
then<TResult1 = T, TResult2 = never>(onfulfilled?: ((value: T) => TResult1 | PromiseLike<TResult1>) | null | undefined, onrejected?: ((reason: any) => TResult2 | PromiseLike<TResult2>) | null | undefined): Promise<TResult1 | TResult2>;
Type Parameters​
Parameter Default Description
TResult1 T
TResult2 never

Parameters​

Parameter Modifiers Type Description
onfulfilled optional ((value: T) => TResult1 | PromiseLike<TResult1>) | null | undefined
onrejected optional ((reason: any) => TResult2 | PromiseLike<TResult2>) | null | undefined

Returns​

Return type: Promise<TResult1 | TResult2>