测试子字符串是否为数字，并且是否大于Javascript中的另一个数字

Question

I have a json file that has a string as the pubDate. The pubDate could be 2010 or 2010 Mar or 2010/1/1 or Blank or Not available. What I have is

var res = pubDate.substr(0, 4);
var i = parseInt(res, 10);
if (!isNaN(i)) {                    
    if (i > 2010) {
        //do work
    }
}

This works but I'd love to have some cleaner code where I might be able to do it in one or two lines of code. This this possible?

Answer 1

1) If i is NaN , i > 2010 will be false, so the isNaN check is not neccessary.

2) ParseInt ignores suffix characters, so you don't have to substr:

const year = parseInt(pubDate);
if(year > 2010) {
  //...
 }

Answer 2

That's a pretty messy situation it sounds like, short of collapsing some of those lines I don't think you have much of an option. By collapsing some of the lines I mean literally:

var i = parseInt((pubDate.substr(0, 4), 10);
if (!isNan(i) && i > 2010) {
    // do work
}

But this is assuming you don't need "res" for something later, which looks like you shouldn't.

Answer 3

Maybe two lines of code. Maybe not cleaner code.

var i = (!isNaN(parseInt(pubDate.substr(0, 4))))?parseInt(pubDate.substr(0, 4)):0;
if( i > 2010 ){
    //do work
}

Answer 4

If you are not looking for decimal specific you could remove the 10. More information about this on https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/parseInt

var i = parseInt(pubDate.substr(0, 4));
if (!isNaN(i) && i > 2010) { 
     //do work
}