@thi.ng/memoize

This project is part of the @thi.ng/umbrella monorepo.

• About
  • Status
• Installation
• Dependencies
• Usage examples
• API
  • Optimized version for single arg functions
  • Arbitrary args
  • Via JSON.stringify()
• Authors
• License

About

Function memoization with configurable caching.

This package provides different function memoization implementations for functions with 1 or more arguments and custom result caching using ES6 Map API like implementations. Unlike native ES6 Maps, the implementations MUST support value, not just referential, equality semantics (e.g. those provided by @thi.ng/associative) or @thi.ng/cache). The latter also support automatically pruning of memoization caches, based on different strategies. See doc strings for further details.

Status

STABLE - used in production

Search or submit any issues for this package

Installation

yarn add @thi.ng/memoize

// ES module
<script type="module" src="https://unpkg.com/@thi.ng/memoize?module" crossorigin></script>

// UMD
<script src="https://unpkg.com/@thi.ng/memoize/lib/index.umd.js" crossorigin></script>

Package sizes (gzipped, pre-treeshake): ESM: 282 bytes / CJS: 336 bytes / UMD: 417 bytes

Dependencies

• @thi.ng/api

Usage examples

Several demos in this repo's /examples directory are using this package.

A selection:

Screenshot	Description	Live demo	Source
	Basic rstream-gestures multi-touch demo	Demo	Source
	rstream based spreadsheet w/ S-expression formula DSL	Demo	Source

API

Generated API docs

import * as m from "@thi.ng/memoize";

// (optional, for custom caching)
import { EquivMap } from "@thi.ng/associative";
import { LRUCache } from "@thi.ng/cache";

Optimized version for single arg functions

foo = m.memoize1((x) => (console.log("exec"), x * 10));
foo(1);
// exec
// 10
foo(1);
// 10

// with custom cache
foo = m.memoize1(
    (x) => (console.log("exec"), x[0] * 10),
    new EquivMap()
);

foo([1]);
// exec
// 10
foo([1]); // wouldn't work w/ native ES6 Map as cache
// 10

// use LRU cache to limit cache size
foo = m.memoize1(
    (x) => (console.log("exec"), x[0] * 10),
    new LRUCache(null, { maxlen: 3 })
);

Arbitrary args

dotProduct = m.memoize(
    (x, y) => (console.log("exec"), x[0] * y[0] + x[1] * y[1]),
    new EquivMap()
);

dotProduct([1,2], [3,4]);
// exec
// 11
dotProduct([1,2], [3,4]);
// 11

Via JSON.stringify()

dotProduct = m.memoizeJ(
    (x, y) => (console.log("exec"), x[0] * y[0] + x[1] * y[1])
);
dotProduct([1,2], [3,4]);
// exec
// 11
dotProduct([1,2], [3,4]);
// 11

Authors

Karsten Schmidt

License

© 2018 - 2020 Karsten Schmidt // Apache Software License 2.0