"a" + + "b" // aNaNWhy is the result of this addition "aNaN", has a boss to explain? Thank you very much
"a" + + "b" // aNaNWhy is the result of this addition "aNaN", has a boss to explain? Thank you very much
+'b' the plus sign here means a plus or minus sign, not an addition operation. A positive or negative sign before a string is converted to the number type.
console.log(typeof '3'); // string
console.log(typeof +'3'); //number'b' string is converted to number, it will be NaN, and then added (concatenated) to the previous'a 'string, NaN is converted to the string' NaN'
.'a' + (+'b')+'b' = NaN
+'b' //NaN
+'1' // 1
forcibly convert the Number type. If the string is numeric, it will be converted to Number,. If not, it will be NaN,. Usually we can do this:
var a = '154544';
+a || +a==0 ? console.log('') : console.log('') the answers of the bosses are more accurate. Let me add some more information:
the rules of conversion
for more detailed content, you need to read the relevant specifications by yourself:
https://tc39.github.io/ecma26.
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