Function: at()
at<
T>(index, …sources):T|undefined
Same semantics as Array.prototype.at over the concatenated sources.
Non-negative indices scan lazily; negative indices materialize first. index
leads so the sources can stay variadic.
Type Parameters
Section titled “Type Parameters”T
Parameters
Section titled “Parameters”number
Zero-based position; negative counts from the end.
sources
Section titled “sources”…readonly Source<T>[]
Containers to concatenate (nullish sources are skipped).
Returns
Section titled “Returns”T | undefined