flat

The flat() method flattens a nested array up to the requested depth and returns a new array containing the unrolled elements.

Interactive example

Syntax

function flat<
	const GenericInput extends readonly unknown[],
	const GenericDepth extends number = 1
>(
	input: GenericInput,
	depth?: GenericDepth
): FlatArray<GenericInput, GenericDepth>[]

Parameters

• input: The potentially nested array to flatten.
• depth: The number of levels to unroll. Defaults to 1.

Return value

A new array in which the elements have been concatenated up to the requested depth. If the input is a tuple, the resulting type precisely reflects the flattening level.

See also

• flatMap - Transforms then flattens the result by one level
• map - Applies a function to each element

Sources

• MDN Web Docs - Array.prototype.flat()