What is the difference between new Date and +new Date?
For example:
var date = new Date;
console.log(date);
var plusDate = +new Date;
console.log(plusDate);
Logs:
Sat May 10 2014 01:13:46 GMT+0300 (Jordan Standard Time)
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Looks like this question has been asked: http://stackoverflow.com/questions/221539/what-does-the-plus-sign-do-in-return-new-date – user3473534 May 09 '14 at 22:25
2 Answers
3
The unary plus operator casts the Date object to a Number object (which is expressed in in milliseconds since 01 January, 1970 UTC).
Quentin
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+1 - Does it implicitly call `.value`? Does date do the conversion internally or is it done somewhere else? – Travis J May 09 '14 at 22:24
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@TravisJ—it's all [*in the spec*](http://ecma-international.org/ecma-262/5.1/#sec-11.4.6). – RobG May 09 '14 at 22:25
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@RobG - Where in the spec does it mention calling .valueOf()? Because that is actually what seems to happen implicitly. http://jsfiddle.net/gcaFu/ – Travis J May 09 '14 at 22:27
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@RobG - I see, "ToNumber(GetValue(expr))" calls GetValue, which "let getter be desc.[[Get]]" for the `expr` in which case `.valueOf()` is called. Date overrides object.prototype.valueOf and returns its time value. Thanks for the links :) – Travis J May 09 '14 at 22:36
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The first one creates a Date object, the second one adds the current date value in milliseconds to the original value of plusDate, which was 0.
tempoc
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