# cache-advice

> function decorators for caching

Latest version **0.1.0** (published 2013-08-23) · 0 weekly downloads

## Install

```sh
npm install cache-advice
pnpm add cache-advice
yarn add cache-advice
bun add cache-advice
```

## Health

**Score 15/100 (F)** — status: abandoned.

Positive: no vulnerabilities.

Warnings: low downloads; no types; no esm support; pre 1.0.

Negative: abandoned; low maintenance score.

## Facts

| | |
|---|---|
| Version | 0.1.0 |
| Published | 2013-08-23 |
| First published | 2013-03-13 |
| Weekly downloads | 0 |
| TypeScript types | none |
| Module format | CommonJS |
| Node | * |
| Dependencies | 1 |
| Known vulnerabilities | 0 |
| Install scripts | no |
| GitHub stars | 0 |
| Author | Matthew Lyon |
| Maintainers | mattly |
| Keywords | cache, functional, aspect-oriented-programming |

## Links

- npm: https://www.npmjs.com/package/cache-advice
- Repository: https://github.com/mattly/node-cache-advice
- Issues: https://github.com/mattly/node-cache-advice/issues
- npm.io page: https://npm.io/package/cache-advice

## Dependencies (1)

- [lru-cache](https://npm.io/package/lru-cache.md) 2.2.x

## Alternatives

- [memory-cache](https://npm.io/package/memory-cache.md) — 795.0K weekly downloads
- [@httptoolkit/proxy-agent](https://npm.io/package/@httptoolkit/proxy-agent.md) — 11.2K weekly downloads
- [express-cache-controller](https://npm.io/package/express-cache-controller.md) — 5.3K weekly downloads
- [http-cache-middleware](https://npm.io/package/http-cache-middleware.md) — 4.5K weekly downloads
- [cache2](https://npm.io/package/cache2.md) — 1.5K weekly downloads

## Recent versions

- 0.1.0 (latest) — 2013-08-23
- 0.0.6 — 2013-04-15
- 0.0.5 — 2013-04-02
- 0.0.4 — 2013-03-14
- 0.0.3 — 2013-03-14
- 0.0.2 — 2013-03-14
- 0.0.1 — 2013-03-13

## README

# Cache Advice

by Matthew Lyon <matthew@lyonheart.us>

[![Build Status](https://travis-ci.org/mattly/node-cache-advice.png?branch=master)](https://travis-ci.org/mattly/node-cache-advice)

A javascript module for caching the results of functions that take callbacks in
the node [err, response] pattern. Useful for decorating functions that make slow
database calls, http requests, etc.

The caching mechanism is pluggable, by default will use [lru-cache][]. Other
stores:

- [redis][redis-advice]

Coming soon:

- memcached
- riak
- sql table

[lru-cache]: https://github.com/isaacs/node-lru-cache
[redis-advice]: https://github.com/mattly/node-cache-advice-redis

## Example

    var cacher = require('cache-advice')();
    var getter = cacher.readThrough(reallySlowDbQuery);

    // will call `reallySlowDbQuery(params)`, store results in cache at the key
    // generated by `Array.prototype.slice.call(arguments).join()`. You can
    // override the key generator.
    var now = Date.now();
    getter(params, function(err, result){
      console.log("took %d ms", Date.now() - now);
    });

    setTimeout(function(){
      var now = Date.now();
      // will check the cache first, if found will serve from that
      getter(params, function(err, result){
        console.log("took %d ms", Date.now() - now);
      });
      }, 2000);

# Public API

### cacheAdvice(state)
Returns an advice giver, refered to as 'advice' below. State is an object with
any of the following keys:

- *cache*: An object with functions at the keys:
    - *get(key, callback)*: retrives an item from the cache, provides to
      callback.
    - *set(key, value, callback)*: stores an item in the cache.
    - *del(key, callback)*: removes an item from the cache.

    If not provided, will default to a wrapper of [node-lru][lru-cache].
- *prefix*: Will prefix keys with this string.
- *keyStrategy*: Given `Array.prototype.slice.call(arguments)`, returns the key
  to use for a given function.

## Configuration

### advice.prefix(prefixStr)

- **prefix**: String. If given, forks the advice with a new prefix. If not
  given, returns the existing prefix.

### advice.appendPrefix(prefixStr)

- **prefix** (required): String. Forks the advice strategy, appending the given
  string to the current one.

### advice.keyStrategy(fn)

- **fn**: Function. If given, forks the advice with a new key generation
  strategy function. If not given, returns the existnig key generation strategy.
  The default function is:

      function(){ return Array.prototype.join.apply(arguments); }

  The function will receive all arguments to the function except the final
  callback argument.

## Function Decorators

Will augment a provided function that conforms to the node.js callback pattern
(that is, is called with [arg1, arg2, ..., callback] and calls the callback with
[err, result1, result2, ...]) with a strategy for managing a the results in
a cache. The arguments to the function are used to generate the cache key using
the prefix and strategies in the config, and the results are provided to the
actual cache as an array, typically to be serialized via JSON.

### advice.updates(fn)

Will call `fn` with provided arguments and update the cache key for the provided
arguments with the result.

### advice.readThrough(fn)

Will check the cache first. On a hit, will provide cached results. On a miss,
will call `fn` with provided arguments and update the cache key for the provided
arguments with the result.

### advice.expires(fn)

Will expire the cache key for the provided arguments, then call `fn` with them.

---
_Source: https://npm.io/package/cache-advice · Machine-readable twin of the npm.io package page. Health data is recomputed on every publish._