get-nans 
JavaScript should only have one distinguishable NaN value. However, some engines violate this, and have at least two.
This module returns an array of all the NaNs it knows how to detect on the current engine.
Current engines with only one observable NaN value:
- Edge v14
Current known failures:
node(v0.6-v0.12,v4.0-v6.3.1)io.js(all versions)- Chrome (
v43-v52, at least) - Firefox (
v38-v47, at least) - Internet Explorer (
v10-v11)
Example
var getNaNs = require('get-nans');
var assert = require('assert');
var nans = getNaNs();
assert.deepEqual(nans, [NaN]);Relevant links
- https://esdiscuss.org/topic/observability-of-nan-distinctions-is-this-a-concern
- https://bugs.webkit.org/show_bug.cgi?id=53598
- https://code.google.com/p/v8/issues/detail?id=1101
- https://people.mozilla.org/~jorendorff/es6-draft.html#sec-ecmascript-language-types-number-type - see "Note"
- https://bugs.ecmascript.org/show_bug.cgi?id=3508
Tests
Simply clone the repo, npm install, and run npm test