8 });
9
10 return filtro?.map((item) => (
11 <div className="item" key={parseInt(item.objectID)}>12 <Book item={item} />
13 </div>
14 ));When using the parseInt() function it is common to omit the second argument, the radix, and let the function try to determine from the first argument what type of number it is.
By default, parseInt() will autodetect decimal and hexadecimal (via 0x prefix).
Prior to ECMAScript 5, parseInt() also autodetected octal literals, which caused problems because many developers assumed a leading 0 would be ignored.
This confusion led to the suggestion that you always use the radix parameter to parseInt() to eliminate unintended consequences. So instead of doing this:
let num = parseInt("071"); // 57
Do this:
let num = parseInt("071", 10); // 71
ECMAScript 5 changed the behavior of parseInt() so that it no longer autodetects octal literals and instead treats them as decimal literals.
However, the differences between hexadecimal and decimal interpretation of the first parameter causes many developers to continue using the radix parameter to ensure the string is interpreted in the intended way.
On the other hand, if the code is targeting only ES5-compliant environments passing the radix 10 may be redundant.
In such a case you might want to disallow using such a radix.
Bad Practice
let num = parseInt("071");
num = parseInt(someValue);
num = parseInt("071", "abc");
num = parseInt();
Recommended
let num = parseInt("071", 10);
num = parseInt("071", 8);
num = parseFloat(someValue);