minElements

The minElements() function checks that an array contains at least a given number of elements. It acts as a type guard, which allows TypeScript to infer a tuple of at least minLength elements.

Interactive example

Syntax

Classic signature

function minElements<
	GenericInput extends readonly unknown[],
	GenericLength extends number
>(
	input: GenericInput,
	minLength: GenericLength
): input is [
	...CreateTuple<GenericInput[number], GenericLength>,
	...GenericInput[number][]
]

Curried signature

function minElements<
	GenericInput extends readonly unknown[],
	GenericLength extends number
>(
	minLength: GenericLength
): (
	input: GenericInput
) => input is [
	...CreateTuple<GenericInput[number], GenericLength>,
	...GenericInput[number][]
]

Parameters

• input: Array for which you want to guarantee a minimum number of elements.
• minLength: Expected minimum number.

Return value

true if the array length is greater than or equal to minLength, otherwise false. When the function returns true, the array type is narrowed to reflect the constraint.

See also

• maxElements - Imposes a maximum number of elements
• length - Returns the exact size of an array

Sources

• MDN Web Docs - Array.length