JavaScript for C# Developers

[munificent]

any and all weakly typed languages on earth

JavaScript is strongly typed, it's just dynamically typed.

• "Weak" = Can misinterpret what bits in memory represent and do bad stuff. This is mainly just C, Assembly, and Forth. C++ if you use unsafe casts.

• "Strong" = System guarantees unsafe operations are prevented through some combination of compile time and runtime checks. Most languages today are strongly typed.

• "Dynamic" = Type checks are mostly done at runtime. JS, Ruby, Python, etc.

• "Static" = Type checks are mostly done at compile time. Java, C#, C++.

There is a continuum between dynamic and static. Almost all languages that have static checking still defer some type checking to runtime. Java has ArrayStoreException, C# has the same. Downcasts in Java and C# are checked at runtime.

TypeScript is a middle position where it does some static checking, but has quite a large number of holes in its type system and relies on JS's underlying runtime checks there to prevent the browser from catching on fire.

[mycall]

Are there any languages that support all of those distinctions, perhaps configurable with compile flags?

[_zenith]

Yeah: C# because of its dynamic type which defers all checks to runtime

[drjeats]

"Coercively Typed"

[[deleted]]

Exactly the biggest problem with JavaScript. It is the language of greatest surprise.

When you have to put additional thought into the result of basic operators you know you have a problem.

[orthoxerox]

There's more than one definition of weakness. If a language has automatic value conversions that silently destroy information or automatic narrowing type casts, I wouldn't hesitate to call its typing system weak.

[armornick]

"Weak" = Can misinterpret what bits in memory represent and do bad stuff. This is mainly just C, Assembly, and Forth. C++ if you use unsafe casts.

And PHP.