The arithmetic "+" operator

The binary + operator is generally used to add two numbers, when both of the operands are just numbers it will give the sum(quite obvious)

But when one of the operands is a string then the + acts as a string concatenation operator.

The other operand if it is a number, it will be converted into a string.

2+2=42+"2"="22""2"+2="22""2"+"2"="22"

The arithmetic “ — “ operator

The - operator only operates with numbers only.

If both operators are numbers, it will do the casual subtraction. If the operators are numbers represented in strings, it will just convert those into numbers.

If there exist any character strings like "hello" , it will just result in NaN.

2-5=-35-4=1"500"-100=400"50"-"19"=31"adarsh"-9=NAN

Precedence of “+” and “-” operator

We know the BODMAS rule from our high school, here addition and subtraction got the same priority or precedence.

Hence it will evaluate from left to right.

"100"+200-"150"  //will start from this"100"+"200"-"150""100200"-"2"100200-2100198 //will end like this

Unlike many other high-level languages out there, JavaScript is a dynamically typed language and is not strict about the datatypes of the operand.

When the operands are of different types it will convert them into suitable types instead of showing errors

These cannot be called a weirdness or a feature of JavaScript. These are just how JavaScript works under the hood.

In simple word + is both a concatenation as well as an addition operator. If any operands/arguments are not m=numeric it will do concatenation, that's why "2"+"2" == 22 just like "adarsh”+" gupta" == “adarsh gupta”.

- is only subtraction. No matter what its arguments are, they are coerced to numbers. Thus, '22' - '2' is evaluated as 22 - 2 which is 20.

Conclusion

We have learned why the + operator does both concatenation and addition in different scenarios.

I hope you have found these useful. Be sure to follow me on Twitter as I’m active there too.

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