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