What is the application of the plus operator in these cases? I have seen it used in these ways but don't see how it operates.
start = +new Date;
+array[i]
+f.call(array, array[i], i)
x = +y
-
One more: stackoverflow.com/questions/8330499/…bfavaretto– bfavaretto2013-05-17 20:27:34 +00:00Commented May 17, 2013 at 20:27
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1 Answer
+ will implicitly cast a string / boolean value into a Number().
+"66" === 66
If the string cannot be converted into a Number, the value will be NaN
+"not possible" // evaluates to NaN
In the case of a Date() object, + will also cast the data into its numerical representation, that is the UNIX timestamp.
So, finally spoken, leading an expression with + is pretty much the same as explicitly wrapping the Number() constructor around it:
+new Date()
equals
Number( new Date() )
1 Comment
dandavis
or any primitive value into a number for that matter...