JavaScript Coercions Grid

Exception!

Value Coercion WTF

Fixed WTF

This tool is designed to help visualize JS's value coercion corner cases, specifically the ones that are WTFs, and to see what effect fixing some or all of them can have on the landscape of values.

For lots more information on this topic, please check out Fixing Coercion, Not The Symptoms and You Don't Know JS: Types & Grammar.

← You should try this!

settings

hide extra columns
mark value coercion wtfs

Fix Value Coercions (aka "use proper") Number("") → NaN
Number(null) → NaN
Number(true), Number(false) → NaN
String([..]), Number([..]) → '[..]', NaN
String({..}), Number({..}) → '{..}', NaN

Extended Coercions

Note: These are all deliberately tricky objects and as such the "proper" coercive behavior is a lot more subject to debate. I'll leave these unmarked (for now).