map-memo


Generic memoization using Map and WeakMap.

---

$3

``
npm install --save @starryinternet/map-memo
`

---

$3

Memoization in JavaScript has typically been limited to arguments
with primitive values, or by utilizing hacks such as stringifying objects.

By storing arguments using a series of nested cache objects backed by Map
and WeakMap, map-memo is able to memoize functions with any
argument types.

---

$3

`js
'use strict';

const memoize = require('@starryinternet/map-memo');

function loop( fn, n ) {
let v;

for ( let i = 0; i < n; ++i ) {
v = fn( i );
}

return v;
}

let mem = memoize( loop );

console.log( mem( Math.sqrt, 1e9 ) ); // slow
console.log( mem( Math.sqrt, 1e9 ) ); // fast!
`

$3

`js
'use strict';

const memoize = require('@starryinternet/map-memo');

function getRandom() {
return Math.random();
}

let mem = memoize( getRandom, { ttl: 1000 } );
console.log( mem() );
console.log( mem() ); // Same value as above

setTimeout( function() {
console.log( mem() ); // Different value
}, 1001 );
`

$3

`js
'use strict';

const memoize = require('@starryinternet/map-memo');

function loopAsync( fn, n ) {
return new Promise( ( resolve, reject ) => {
let v;

for ( let i = 0; i < n; ++i ) {
v = fn( i );
}

resolve( v );
});
}

let mem = memoize( loopAsync );

mem( Math.sqrt, 1e9 ).then( result => {
console.log( result ); // slow
mem( Math.sqrt, 1e9 ).then( console.log ); // fast!
});
``