like this:
var foo = 45;
var bar = '' + foo;
Actually, even though I typically do it like this for simple convenience, over 1,000s of iterations it appears for raw speed there is an advantage for .toString()
See Performance tests here (not by me, but found when I went to write my own): http://jsben.ch/#/ghQYR
Fastest based on the JSPerf test above: str = num.toString();
It should be noted that the difference in speed is not overly significant when you consider that it can do the conversion any way 1 Million times in 0.1 seconds.
Update: The speed seems to differ greatly by browser. In Chrome num + '' seems to be fastest based on this test http://jsben.ch/#/ghQYR
Update 2: Again based on my test above it should be noted that Firefox 20.0.1 executes the .toString() about 100 times slower than the '' + num sample.
like this:
var foo = 45;
var bar = '' + foo;
Actually, even though I typically do it like this for simple convenience, over 1,000s of iterations it appears for raw speed there is an advantage for .toString()
See Performance tests here (not by me, but found when I went to write my own): http://jsben.ch/#/ghQYR
Fastest based on the JSPerf test above: str = num.toString();
It should be noted that the difference in speed is not overly significant when you consider that it can do the conversion any way 1 Million times in 0.1 seconds.
Update: The speed seems to differ greatly by browser. In Chrome num + '' seems to be fastest based on this test http://jsben.ch/#/ghQYR
Update 2: Again based on my test above it should be noted that Firefox 20.0.1 executes the .toString() about 100 times slower than the '' + num sample.
In my opinion n.toString() takes the prize for its clarity, and I don't think it carries any extra overhead.
Videos
The simplest way would be to use the native Number function:
var x = Number("1000")
If that doesn't work for you, then there are the parseInt, unary plus, parseFloat with floor, and Math.round methods.
parseInt()
var x = parseInt("1000", 10); // You want to use radix 10
// So you get a decimal number even with a leading 0 and an old browser ([IE8, Firefox 20, Chrome 22 and older][1])
Unary plus
If your string is already in the form of an integer:
var x = +"1000";
floor()
If your string is or might be a float and you want an integer:
var x = Math.floor("1000.01"); // floor() automatically converts string to number
Or, if you're going to be using Math.floor several times:
var floor = Math.floor;
var x = floor("1000.01");
parseFloat()
If you're the type who forgets to put the radix in when you call parseInt, you can use parseFloat and round it however you like. Here I use floor.
var floor = Math.floor;
var x = floor(parseFloat("1000.01"));
round()
Interestingly, Math.round (like Math.floor) will do a string to number conversion, so if you want the number rounded (or if you have an integer in the string), this is a great way, maybe my favorite:
var round = Math.round;
var x = round("1000"); // Equivalent to round("1000", 0)
Try parseInt function:
var number = parseInt("10");
But there is a problem. If you try to convert "010" using parseInt function, it detects as octal number, and will return number 8. So, you need to specify a radix (from 2 to 36). In this case base 10.
parseInt(string, radix)
Example:
var result = parseInt("010", 10) == 10; // Returns true
var result = parseInt("010") == 10; // Returns false
Note that parseInt ignores bad data after parsing anything valid.
This guid will parse as 51:
var result = parseInt('51e3daf6-b521-446a-9f5b-a1bb4d8bac36', 10) == 51; // Returns true