side-channel-weakmap 

Store information about any JS value in a side channel. Uses WeakMap if available.

Warning: this implementation will leak memory until you delete the key. Use side-channel for the best available strategy.

Getting started

npm install --save side-channel-weakmap

Usage/Examples

const assert = require('assert');
const getSideChannelList = require('side-channel-weakmap');

const channel = getSideChannelList();

const key = {};
assert.equal(channel.has(key), false);
assert.throws(() => channel.assert(key), TypeError);

channel.set(key, 42);

channel.assert(key); // does not throw
assert.equal(channel.has(key), true);
assert.equal(channel.get(key), 42);

channel.delete(key);
assert.equal(channel.has(key), false);
assert.throws(() => channel.assert(key), TypeError);

Tests

Clone the repo, npm install, and run npm test