Function memorize

memorize the return value of a single parameter function. further calls with memorized arguments will return the value much quicker.

Example

import { assertEquals as assertEq } from "jsr:@std/assert"

let fn_call_count = 0
const fn = (arg: string | number) => {
	fn_call_count++
	return `you owe ${arg} to the bank.`
}
const memorized_fn = memorize(fn)

assertEq(memorized_fn("a camel")  , "you owe a camel to the bank.")
assertEq(fn_call_count            , 1)
assertEq(memorized_fn("a camel")  , "you owe a camel to the bank.")
assertEq(fn_call_count            , 1)
assertEq(memorized_fn("5")        , "you owe 5 to the bank.")
assertEq(fn_call_count            , 2)
assertEq(memorized_fn(5)          , "you owe 5 to the bank.")
assertEq(fn_call_count            , 3)
assertEq(memorized_fn("your soul"), "you owe your soul to the bank.")
assertEq(fn_call_count            , 4)
assertEq(memorized_fn("your soul"), "you owe your soul to the bank.")
assertEq(fn_call_count            , 4)

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