Cache the result of a function

Problem

In your modules (or somewhere else) sometimes you have expensive calculations to make, or you simply want to cache a result of a method/function, when its parameters/data do not change on runtime and it’s still accessed multiple times.

Note: This a runtime cache, nothing is saved to disk or the database.

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Solution

function expensiveStuff($name, $someOtherParam, $forceNew = false)
{
    // This static $cache is scoped to the function and will be created only
    // once despite called multiple times
    static $cache = null;
    if (is_null($cache)) $cache = array();

    // Generate a unique ID here, this is just an example
    $id = "{$name}-{$someOtherParam}";

    // Return the cached result if it exists _and_ it should not be recalculated
    if (!$forceNew && array_key_exists($id, $cache)) return $cache[$id];

    $result = '... expensive code here ...';

    // Save the result in the cache and return it
    return $cache[$id] = $result;
}

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Resources