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micro-memoize
Advanced tools
micro-memoize is a tiny, performant memoization library for JavaScript. It is designed to cache the results of function calls to improve performance, especially for expensive or frequently called functions. The library is highly configurable and supports various options for customizing the memoization behavior.
Basic Memoization
This feature allows you to memoize a function so that its results are cached. Subsequent calls with the same arguments will return the cached result instead of recomputing.
const memoize = require('micro-memoize');
const expensiveFunction = (num) => {
console.log('Computing...');
return num * num;
};
const memoizedFunction = memoize(expensiveFunction);
console.log(memoizedFunction(5)); // Computing... 25
console.log(memoizedFunction(5)); // 25 (cached result)
Custom Cache Size
This feature allows you to set a custom cache size. Once the cache exceeds this size, the oldest cached results are discarded.
const memoize = require('micro-memoize');
const expensiveFunction = (num) => {
console.log('Computing...');
return num * num;
};
const memoizedFunction = memoize(expensiveFunction, { maxSize: 2 });
console.log(memoizedFunction(5)); // Computing... 25
console.log(memoizedFunction(6)); // Computing... 36
console.log(memoizedFunction(5)); // 25 (cached result)
console.log(memoizedFunction(7)); // Computing... 49
console.log(memoizedFunction(6)); // 36 (cached result)
console.log(memoizedFunction(5)); // Computing... 25 (cache size exceeded, recomputed)
Custom Equality Function
This feature allows you to provide a custom equality function to determine if two arguments are equivalent. This is useful for complex data structures where simple equality checks are insufficient.
const memoize = require('micro-memoize');
const expensiveFunction = (obj) => {
console.log('Computing...');
return obj.value * obj.value;
};
const isEqual = (a, b) => a.value === b.value;
const memoizedFunction = memoize(expensiveFunction, { isEqual });
console.log(memoizedFunction({ value: 5 })); // Computing... 25
console.log(memoizedFunction({ value: 5 })); // 25 (cached result)
lodash.memoize is a memoization function from the Lodash library. It provides basic memoization capabilities and is widely used due to Lodash's popularity. However, it may not be as performant or configurable as micro-memoize.
memoizee is a highly configurable memoization library that supports various features like cache expiration, custom resolvers, and more. It is more feature-rich compared to micro-memoize but also larger in size.
fast-memoize is a fast and efficient memoization library focused on performance. It is similar to micro-memoize in terms of speed but offers fewer configuration options.
A tiny, crazy fast memoization library for the 95% use-case
As the author of moize
, I created a consistently fast memoization library, but moize
has a lot of features to satisfy a large number of edge cases. micro-memoize
is a simpler approach, focusing on the core feature set with a much smaller footprint (~1.44kB minified+gzipped). Stripping out these edge cases also allows micro-memoize
to be faster across the board than moize
.
ESM in browsers:
import memoize from 'micro-memoize';
ESM in NodeJS:
import memoize from 'micro-memoize/mjs';
CommonJS:
const memoize = require('micro-memoize');
const assembleToObject = (one: string, two: string) => ({ one, two });
const memoized = memoize(assembleToObject);
console.log(memoized('one', 'two')); // {one: 'one', two: 'two'}
console.log(memoized('one', 'two')); // pulled from cache, {one: 'one', two: 'two'}
If you need them, all types are available under the MicroMemoize
namespace.
import { MicroMemoize } from 'micro-memoize';
Starting in 4.0.0
, you can compose memoized functions if you want to have multiple types of memoized versions based on different options.
const simple = memoized(fn); // { maxSize: 1 }
const upToFive = memoized(simple, { maxSize: 5 }); // { maxSize: 5 }
const withCustomEquals = memoized(upToFive, { isEqual: deepEqual }); // { maxSize: 5, isEqual: deepEqual }
NOTE: The original function is the function used in the composition, the composition only applies to the options. In the example above, upToFive
does not call simple
, it calls fn
.
function(object1: any, object2: any): boolean
, defaults to isSameValueZero
Custom method to compare equality of keys, determining whether to pull from cache or not, by comparing each argument in order.
Common use-cases:
import { deepEqual } from 'fast-equals';
type ContrivedObject = {
deep: string;
};
const deepObject = (object: {
foo: ContrivedObject;
bar: ContrivedObject;
}) => ({
foo: object.foo,
bar: object.bar,
});
const memoizedDeepObject = memoize(deepObject, { isEqual: deepEqual });
console.log(
memoizedDeepObject({
foo: {
deep: 'foo',
},
bar: {
deep: 'bar',
},
baz: {
deep: 'baz',
},
}),
); // {foo: {deep: 'foo'}, bar: {deep: 'bar'}}
console.log(
memoizedDeepObject({
foo: {
deep: 'foo',
},
bar: {
deep: 'bar',
},
baz: {
deep: 'baz',
},
}),
); // pulled from cache
NOTE: The default method tests for SameValueZero equality, which is summarized as strictly equal while also considering NaN
equal to NaN
.
function(object1: any[], object2: any[]): boolean
Custom method to compare equality of keys, determining whether to pull from cache or not, by comparing the entire key.
Common use-cases:
import { deepEqual } from 'fast-equals';
type ContrivedObject = { foo: string; bar: number };
const deepObject = (object: ContrivedObject) => ({
foo: object.foo,
bar: object.bar,
});
const memoizedShape = memoize(deepObject, {
// receives the full key in cache and the full key of the most recent call
isMatchingKey(key1, key2) {
const object1 = key1[0];
const object2 = key2[0];
return (
object1.hasOwnProperty('foo') &&
object2.hasOwnProperty('foo') &&
object1.bar === object2.bar
);
},
});
console.log(
memoizedShape({
foo: 'foo',
bar: 123,
baz: 'baz',
}),
); // {foo: {deep: 'foo'}, bar: {deep: 'bar'}}
console.log(
memoizedShape({
foo: 'not foo',
bar: 123,
baz: 'baz',
}),
); // pulled from cache
boolean
, defaults to false
Identifies the value returned from the method as a Promise
, which will result in one of two possible scenarios:
onCacheHit
and onCacheChange
optionsconst fn = async (one: string, two: string) => {
return new Promise((resolve, reject) => {
setTimeout(() => {
reject(new Error(JSON.stringify({ one, two })));
}, 500);
});
};
const memoized = memoize(fn, { isPromise: true });
memoized('one', 'two');
console.log(memoized.cache.snapshot.keys); // [['one', 'two']]
console.log(memoized.cache.snapshot.values); // [Promise]
setTimeout(() => {
console.log(memoized.cache.snapshot.keys); // []
console.log(memoized.cache.snapshot.values); // []
}, 1000);
NOTE: If you don't want rejections to auto-remove the entry from cache, set isPromise
to false
(or simply do not set it), but be aware this will also remove the cache listeners that fire on successful resolution.
number
, defaults to 1
The number of values to store in cache, based on a Least Recently Used basis. This operates the same as maxSize
on moize
, with the exception of the default being different.
const manyPossibleArgs = (one: string, two: string) => [one, two];
const memoized = memoize(manyPossibleArgs, { maxSize: 3 });
console.log(memoized('one', 'two')); // ['one', 'two']
console.log(memoized('two', 'three')); // ['two', 'three']
console.log(memoized('three', 'four')); // ['three', 'four']
console.log(memoized('one', 'two')); // pulled from cache
console.log(memoized('two', 'three')); // pulled from cache
console.log(memoized('three', 'four')); // pulled from cache
console.log(memoized('four', 'five')); // ['four', 'five'], drops ['one', 'two'] from cache
NOTE: The default for micro-memoize
differs from the default implementation of moize
. moize
will store an infinite number of results unless restricted, whereas micro-memoize
will only store the most recent result. In this way, the default implementation of micro-memoize
operates more like moize.simple
.
function(cache: Cache, options: Options): void
Callback method that executes whenever the cache is added to. This is mainly to allow for higher-order caching managers that use micro-memoize
to perform superset functionality on the cache
object.
const fn = (one: string, two: string) => [one, two];
const memoized = memoize(fn, {
maxSize: 2,
onCacheAdd(cache, options) {
console.log('cache has been added to: ', cache);
console.log('memoized method has the following options applied: ', options);
},
});
memoized('foo', 'bar'); // cache has been added to
memoized('foo', 'bar');
memoized('foo', 'bar');
memoized('bar', 'foo'); // cache has been added to
memoized('bar', 'foo');
memoized('bar', 'foo');
memoized('foo', 'bar');
memoized('foo', 'bar');
memoized('foo', 'bar');
NOTE: This method is not executed when the cache
is manually manipulated, only when changed via calling the memoized method.
function(cache: Cache, options: Options): void
Callback method that executes whenever the cache is added to or the order is updated. This is mainly to allow for higher-order caching managers that use micro-memoize
to perform superset functionality on the cache
object.
const fn = (one: string, two: string) => [one, two];
const memoized = memoize(fn, {
maxSize: 2,
onCacheChange(cache, options) {
console.log('cache has changed: ', cache);
console.log('memoized method has the following options applied: ', options);
},
});
memoized('foo', 'bar'); // cache has changed
memoized('foo', 'bar');
memoized('foo', 'bar');
memoized('bar', 'foo'); // cache has changed
memoized('bar', 'foo');
memoized('bar', 'foo');
memoized('foo', 'bar'); // cache has changed
memoized('foo', 'bar');
memoized('foo', 'bar');
NOTE: This method is not executed when the cache
is manually manipulated, only when changed via calling the memoized method. When the execution of other cache listeners (onCacheAdd
, onCacheHit
) is applicable, this method will execute after those methods.
function(cache: Cache, options: Options): void
Callback method that executes whenever the cache is hit, whether the order is updated or not. This is mainly to allow for higher-order caching managers that use micro-memoize
to perform superset functionality on the cache
object.
const fn = (one: string, two: string) => [one, two];
const memoized = memoize(fn, {
maxSize: 2,
onCacheHit(cache, options) {
console.log('cache was hit: ', cache);
console.log('memoized method has the following options applied: ', options);
},
});
memoized('foo', 'bar');
memoized('foo', 'bar'); // cache was hit
memoized('foo', 'bar'); // cache was hit
memoized('bar', 'foo');
memoized('bar', 'foo'); // cache was hit
memoized('bar', 'foo'); // cache was hit
memoized('foo', 'bar'); // cache was hit
memoized('foo', 'bar'); // cache was hit
memoized('foo', 'bar'); // cache was hit
NOTE: This method is not executed when the cache
is manually manipulated, only when changed via calling the memoized method.
function(Array<any>): any
A method that allows you transform the key that is used for caching, if you want to use something other than the pure arguments.
const ignoreFunctionArgs = (one: string, two: () => {}) => [one, two];
const memoized = memoize(ignoreFunctionArgs, {
transformKey: (args) => [JSON.stringify(args[0])],
});
console.log(memoized('one', () => {})); // ['one', () => {}]
console.log(memoized('one', () => {})); // pulled from cache, ['one', () => {}]
If your transformed keys require something other than SameValueZero
equality, you can combine transformKey
with isEqual
for completely custom key creation and comparison.
const ignoreFunctionArg = (one: string, two: () => void) => [one, two];
const memoized = memoize(ignoreFunctionArg, {
isMatchingKey: (key1, key2) => key1[0] === key2[0],
// Cache based on the serialized first parameter
transformKey: (args) => [JSON.stringify(args[0])],
});
console.log(memoized('one', () => {})); // ['one', () => {}]
console.log(memoized('one', () => {})); // pulled from cache, ['one', () => {}]
Object
The cache
object that is used internally. The shape of this structure:
{
keys: any[][], // available as MicroMemoize.Key[]
values: any[] // available as MicroMemoize.Value[]
}
The exposure of this object is to allow for manual manipulation of keys/values (injection, removal, expiration, etc).
const method = (one: string, two: string) => ({ one, two });
const memoized = memoize(method);
memoized.cache.keys.push(['one', 'two']);
memoized.cache.values.push('cached');
console.log(memoized('one', 'two')); // 'cached'
NOTE: moize
offers a variety of convenience methods for this manual cache
manipulation, and while micro-memoize
allows all the same capabilities by exposing the cache
, it does not provide any convenience methods.
Object
This is identical to the cache
object referenced above, but it is a deep clone created at request, which will provide a persistent snapshot of the values at that time. This is useful when tracking the cache changes over time, as the cache
object is mutated internally for performance reasons.
function
The original function passed to be memoized.
boolean
Hard-coded to true
when the function is memoized. This is useful for introspection, to identify if a method has been memoized or not.
Object
The options
passed when creating the memoized method.
All values provided are the number of operations per second (ops/sec) calculated by the Benchmark suite. Note that underscore
, lodash
, and ramda
do not support mulitple-parameter memoization (which is where micro-memoize
really shines), so they are not included in those benchmarks.
Benchmarks was performed on an i7 8-core Arch Linux laptop with 16GB of memory using NodeJS version 10.15.0
. The default configuration of each library was tested with a fibonacci calculation based on the following parameters:
35
{number: 35}
35, true
{number: 35}, {isComplete: true}
NOTE: Not all libraries tested support multiple parameters out of the box, but support the ability to pass a custom resolver
. Because these often need to resolve to a string value, a common suggestion is to just JSON.stringify
the arguments, so that is what is used when needed.
This is usually what benchmarks target for ... its the least-likely use-case, but the easiest to optimize, often at the expense of more common use-cases.
Operations / second | |
---|---|
fast-memoize | 59,069,204 |
micro-memoize | 48,267,295 |
lru-memoize | 46,781,143 |
Addy Osmani | 32,372,414 |
lodash | 29,297,916 |
ramda | 25,054,838 |
mem | 24,848,072 |
underscore | 24,847,818 |
memoizee | 18,272,987 |
memoizerific | 7,302,835 |
This is what most memoization libraries target as the primary use-case, as it removes the complexities of multiple arguments but allows for usage with one to many values.
Operations / second | |
---|---|
micro-memoize | 40,360,621 |
lodash | 30,862,028 |
lru-memoize | 25,740,572 |
memoizee | 12,058,375 |
memoizerific | 6,854,855 |
ramda | 2,287,030 |
underscore | 2,270,574 |
Addy Osmani | 2,076,031 |
mem | 2,001,984 |
fast-memoize | 1,591,019 |
This is a very common use-case for function calls, but can be more difficult to optimize because you need to account for multiple possibilities ... did the number of arguments change, are there default arguments, etc.
Operations / second | |
---|---|
micro-memoize | 33,546,353 |
lru-memoize | 20,884,669 |
memoizee | 7,831,161 |
Addy Osmani | 6,447,448 |
memoizerific | 5,587,779 |
mem | 2,620,943 |
underscore | 1,617,687 |
ramda | 1,569,167 |
lodash | 1,512,515 |
fast-memoize | 1,376,665 |
This is the most robust use-case, with the same complexities as multiple primitives but managing bulkier objects with additional edge scenarios (destructured with defaults, for example).
Operations / second | |
---|---|
micro-memoize | 34,857,438 |
lru-memoize | 20,838,330 |
memoizee | 7,820,066 |
memoizerific | 5,761,357 |
mem | 1,184,550 |
ramda | 1,034,937 |
underscore | 1,021,480 |
Addy Osmani | 1,014,642 |
lodash | 1,014,060 |
fast-memoize | 949,213 |
Standard stuff, clone the repo and npm install
dependencies. The npm scripts available:
build
=> run webpack to build development dist
file with NODE_ENV=developmentbuild:minifed
=> run webpack to build production dist
file with NODE_ENV=productiondev
=> run webpack dev server to run example app (playground!)dist
=> runs build
and build-minified
lint
=> run ESLint against all files in the src
folderprepublish
=> runs compile-for-publish
prepublish:compile
=> run lint
, test
, transpile:es
, transpile:lib
, dist
test
=> run AVA test functions with NODE_ENV=test
test:coverage
=> run test
but with nyc
for coverage checkertest:watch
=> run test
, but with persistent watchertranspile:lib
=> run babel against all files in src
to create files in lib
transpile:es
=> run babel against all files in src
to create files in es
, preserving ES2015 modules (for pkg.module
)FAQs
A tiny, crazy fast memoization library for the 95% use-case
We found that micro-memoize demonstrated a not healthy version release cadence and project activity because the last version was released a year ago. It has 1 open source maintainer collaborating on the project.
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