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How can I check for “undefined” in JavaScript? [duplicate]
...e undefined, then use the typeof operator, which is guaranteed to return a string:
if (typeof myVar !== 'undefined')
Direct comparisons against undefined are troublesome as undefined can be overwritten.
window.undefined = "foo";
"foo" == undefined // true
As @CMS pointed out, this has been pa...
How do I make a list of data frames?
...f data frames here are three good choices:
# base option - slower but not extra dependencies
big_data = do.call(what = rbind, args = df_list)
# data table and dplyr have nice functions for this that
# - are much faster
# - add id columns to identify the source
# - fill in missing values if some...
The easiest way to transform collection to array?
...of the correct type. And in this case, honestly, I wouldn't care about one extra single empty array in my application. That's far below noise level.
– Andreas Dolk
Jul 21 '10 at 6:28
...
How can I mock dependencies for unit testing in RequireJS?
...str.js didn't work for me, but I've come to the conclusion that the use of extra contexts is actually quite alright and in fact in line with how require.js was meant to be used for mocking/stubbing.
– Chris Salzberg
Jun 24 '13 at 14:10
...
What is the best way to determine the number of days in a month with JavaScript?
...
To take away confusion I would probably make the month string based as it is currently 1 based.
function daysInMonth(month,year) {
monthNum = new Date(Date.parse(month +" 1,"+year)).getMonth()+1
return new Date(year, monthNum, 0).getDate();
}
daysInMonth('feb', 2015)
/...
How to disable mouse scroll wheel scaling with Google Maps API
...
Keep it simple! Original Google maps variable, none of the extra stuff.
var mapOptions = {
zoom: 16,
center: myLatlng,
scrollwheel: false
}
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Set opacity of background image without affecting child elements
... @mystrdat You're already downloading the image, this isn't an extra request.
– brad
Feb 22 '13 at 4:47
2
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What programming practice that you once liked have you since changed your mind about? [closed]
...ian notation (both Forms and Systems).
I used to prefix everything. strSomeString or txtFoo.
Now I use someString and textBoxFoo. It's far more readable and easier for someone new to come along and pick up. As an added bonus, it's trivial to keep it consistant -- camelCase the control and append a u...
What are the differences between the urllib, urllib2, urllib3 and requests module?
...
How does somebody create a url with an encoded query string using urllib2? It's the only reason I'm using urllib and I'd like to make sure I'm doing everything the latest/greatest way.
– Gattster
Jan 7 '10 at 8:51
...
PHP “php://input” vs $_POST
...a lot, this probaby also includes exchanging more complex data with types (string, int, bool) and structures (arrays, objects), so in most cases JSON is the best choice. But a request with a JSON-payload would look something like this:
POST /page.php HTTP/1.1
{"key1":"value1","key2":"value2","key3...