What does the following evaluate to?
"1"+2+4
What about this:
5 + 4 + "3"
In the first case since "1" is a string, everything is a string, so the result is "124". In the second case, its 93.what is happening here? Why does addition happen in one instance, while string concatenation occurs in the other?
var x = "1" + 2 + 4;
var z = 5 + 4 + "3";
console.log(x); // "124"
console.log(z); // 93
Can anyone explain this?
expression evaluates from left to right.
"1"+2+3
^--^
"12" //string +3
^_____________^
"123" //string
in 2nd case
1+2+"3"
^_^
3+"3"
^___^
"33" // string
Think about the operation order (rtl or ltr) each time it performs a binary operation it converts it accordingly so 5+4 will be int and (5+4) + "3" will be a string because "3" is a string
Same method applies to different examples
var x = "1" + 2 + 4; // 124
This is taking the string "1" and concatenating to it "2" and "4" as strings.
var z = 5 + 4 + "3"; // 93
This is taking the numbers 4 and 5 and adding them together to get the number 9, and then concatenating the string "3" to that to produce another string.
The key thing to take away here is that the end result of what you're doing here is string concatenation. The order of evaluating the numbers is different but the end result is a string.
In the first case you create a string first (1) and then javascript concatenates the following number as strings (124).
In the second one you create a number first then javascript adds the second number to this first number (5 + 4 = 9) and then you add a string so it does the concatenation of 9 and 3
In both case apply the type conversion and left to right precedence. in first one,
var x = "1" + 2 + 4; // 124
compiler take 1 as string and after that it will concatenating with 2 now 12 is the string so it will concatenate with 4 and result will produce "124" as string.
var z = 5 + 4 + "3"; // 93
in Second one, first 5 and 4 is numeric so make addition and result will be 9. and this will concatenate with string 3 soo output will be 93 as string.
1 + ""(converts number to string)"3". In the first one"1" + 2gets done first. Which results in a string of"12"..so then it just adds 4 to that string resulting in"124"