function-cache

Cache serializable function calls results.

This module uses Promises (provided by Q).

Installation

npm install --save function-cache

Usage

var cache = require("function-cache");

function foo(param) {
    console.log("foo has been called.");
    return "Foo" + param;
}

var cachedFoo = cache(foo);

cachedFoo("Bar") // Prints "foo has been called." because no cache is available yet.
.then(function(result) {
    console.log(result); // Prints "FooBar"
     
    return cachedFoo("Bar"); // Prints nothing because the result is already cached.
})
.then(function(result) {
    console.log(result); // Prints "FooBar"
     
    return cachedFoo("Plop"); // Prints "foo has been called." because no cache is available yet for this argument.
})
.done();

Options

The cache function can take a second parameter :

var cachedFoo = cache(foo, {
    tmpDir: os.tmpdir(),
    useMemoryCache: true,
    useFileCache: true,
    serializer: JSON.stringify,
    unserializer: JSON.parse,
    hasher: farmhash.hash32,
    tmpPrefix: "function-cache"
});

useMemoryCache

If set to true, a memory cache is used. Defaults to true.

useFileCache

If set to true, files are written and read from the temporary directory. Defaults to true.

tmpDir

This is the path to the folder in which the cache files will be stored (if useFileCache == true). Defaults to os.tmpdir().

tmpPrefix

This is a prefix used in cache files names. Defaults to "function-cache".

hasher

A synchronous function to generate unique hash from given string. Defaults to string-hash.

serializer

A synchronous function to serialize function arguments and result for cache storage. Defaults to JSON.stringify.

unserializer

A synchronous function to unserialize cached function arguments and result. Defaults to JSON.parse.