loop

The loop() function creates a custom generator using a loop function. It lets you generate sequences of values lazily.

Interactive example

Syntax

function loop<
	GenericRawExitOutput extends any = undefined,
	GenericRawNextOutput extends any = undefined,
>(
	loop: (params: GeneratorLoopParams<GenericRawNextOutput>) =>
		| LoopOutputNextResult<GenericRawNextOutput>
		| LoopOutputNextResult<undefined>
		| LoopOutputExistResult<GenericRawExitOutput>
		| LoopOutputExistResult<undefined>
): Generator<
	Exclude<GenericRawExitOutput | GenericRawNextOutput, undefined>,
	unknown,
	unknown
>

Parameters

• loop: Function called at each iteration that receives:
  • count: Index of the current iteration
  • previousOutput: Value returned by the previous iteration
  • next(value?): Continues the loop and emits a value
  • exit(value?): Ends the loop and emits an optional final value

Return value

A Generator that emits the values passed to next() and exit().

See also

• asyncLoop - Asynchronous version of loop
• execute - Consumes a generator
• map - Transforms the elements of a generator

Sources

• MDN Web Docs - Iterators and generators