# Typescript Numeric Literal Types X-Y (Subtraction)

Jun 30, 2022

We have seen how can we add two numeric literals type

now can we apply similar tricks for subtraction?

yes we can, this is how we do it:

`type CreateArrayWithLengthX<`

LENGTH extends number,

ACC extends unknown[] = [],

> = ACC['length'] extends LENGTH

? ACC

: CreateArrayWithLengthX<LENGTH, [...ACC,1]>

type Subtraction<LARGER extends number, SMALLER extends number, GAP extends number[] = []> =

[...GAP,...CreateArrayWithLengthX<SMALLER>]['length'] extends [...CreateArrayWithLengthX<LARGER>]['length']

? GAP['length']

: Subtraction<LARGER, SMALLER, [1,...GAP]>

type result = Subtraction<849, 654> // 195

limitation: the number cannot exceed 999 because the max depth of TS recursion is only 1000, only work with positive integer