Cache the result of an expensive pure function by its arguments. Returns a closure with the same call signature that only invokes the inner function once per unique argument set.
PHP
<?php
function memoize(callable $fn): callable {
$cache = [];
return function (...$args) use ($fn, &$cache) {
$key = md5(serialize($args));
if (!array_key_exists($key, $cache)) {
$cache[$key] = $fn(...$args);
}
return $cache[$key];
};
}
$slowSqrt = memoize(function (int $n) {
sleep(1); // imagine an expensive computation
return sqrt($n);
});
echo $slowSqrt(9); // 3 — first call takes 1 second
echo $slowSqrt(9); // 3 — instant on subsequent calls
echo $slowSqrt(16); // 4 — first call for this argSave your own code snippets
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