Hm, playing devil's advocate, I think it is because the minus has not been defined as a string operation (e.g. it could pop the last char), so it defaults to the mathematical operation and converts both inputs into ints.

The first is assumed to be a concat because one of the parcels is a string...

It's just doing a lot of stuff for you that it shouldn't be in first place 🤭

From all the Javascript quiks this is the least stupid and the most obvious.

pro tip:

"ba" + 0/0 + "a"

Unfortunately, it makes sense if you know what + means, which is concatenate. - is strictly a math function though.

Not saying that makes this better. It just makes sense.

I think I'm on the side of "if you do this in your code, you deserve what you get."

the programming language that had a stated design goal to do its best and try to keep running scripts that make no sense...

...itself makes no sense. It is wrong and bad that Javascript was ever designed that way in the first place.

it would be used by people that have no idea what they are doing. Clearly

And so let's enable these people?
Let's add AI to the mix while we're at it.

Instead of trying to make it work, javascript could just say "error." Being untyped doesn't mean you can't have error messages.

The risk is when it happens unintentionally. The language is bad for hiding such errors by being overly 'helpful' in assuming intent.

The problem is consistency.

Should it, or should it be "1"? (just removing one, one)

BS. A language shouldn't have operators that allow non sensical operations like string concatenation when one operand is not a string.

This is a really good interview, and does a good job highlighting Javascript's biggest strength: it's flexibility.

“It was also an incredible rush job, so there were mistakes in it. Something that I think is important about it is that I knew there would be mistakes, and there would be gaps, so I made it very malleable as a language.”

He cites the “discovery” of asm.js inside of JavaScript, calling it “another thing I’m particularly proud of in the last 10 years.” It uses the bitwise operators that were included in the original JavaScript which are now the basis for a statically-typed language with machine types for high-speed performance. “If it hadn’t been in there from 1995, it would’ve been hard to add later. And the fact that it was there all along meant we could do incredibly fast JavaScript.”

He tells InfoWorld it’s “this very potent seed that was in the original JavaScript from the 10 days of May in 1995.” JavaScript’s 32-bit math operators (known as bitwise operators) trace their lineage all the way back to the C programming language — and to Java. This eventually led to WebAssembly — a way to convert instructions into a quickly-executable binary format for virtual machines — and the realization that with a JavaScript engine, “you can have two languages — the old language I did with the curly braces and the functions and the shift operators, and this new language which is a binary language, not meant for reading by humans or writing. But it can be generated by compilers and tools, and can be read by tools…”

so plus coerces into string if not number, was that so hard?