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How to declare a type as nullable in TypeScript?
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All fields in JavaScript (and in TypeScript) can have the value null or undefined.
You can make the field optional which is different from nullable.
interface Employee1 {
name: string;
salary: number;
}
var a: Employee1 = { name: 'Bob', sal...
Apache POI Excel - how to configure columns to be expanded?
... Just wanted to point out that autoSizeColumn does not scale well and will be super slow if you have lots of rows. I had to get a little hacky and do something similar to what was suggested in this question.
– lbstr
Apr 17 '14 at 20:17
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GetType() can lie?
Based on the following question asked a few days ago in SO: GetType() and polymorphism and reading Eric Lippert's answer, I started thinking if making GetType() not be virtual really ensured that an object could not lie about its Type .
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What does map(&:name) mean in Ruby?
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It's shorthand for tags.map(&:name.to_proc).join(' ')
If foo is an object with a to_proc method, then you can pass it to a method as &foo, which will call foo.to_proc and use that as the method's block.
The Symbol#to_proc meth...
How do I check if an HTML element is empty using jQuery?
...empty')){
//do something
}
for more info see http://api.jquery.com/is/ and http://api.jquery.com/empty-selector/
EDIT:
As some have pointed, the browser interpretation of an empty element can vary. If you would like to ignore invisible elements such as spaces and line breaks and make the imple...
Print number of keys in Redis
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You can issue the INFO command, which returns information and statistics about the server. See here for an example output.
As mentioned in the comments by mVChr, you can use info keyspace directly on the redis-cli.
redis> INFO
# Server
redis_version...
Difference between json.js and json2.js
...mented.
// These forms are obsolete. It is recommended that JSON.stringify and
// JSON.parse be used instead.
if (!Object.prototype.toJSONString) {
Object.prototype.toJSONString = function (filter) {
return JSON.stringify(this, filter);
};
Object.prototype.parseJSON = function (...
What does rake db:test:prepare actually do?
I am following the rails tutorial videos and I can't figure out what the db:test:prepare command actually does. Can someone provide an explanation?
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How can I grep for a string that begins with a dash/hyphen?
...with a dash/hyphen, like -X , in a file, but it's confusing this as a command line argument.
10 Answers
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Inline functions vs Preprocessor macros
...s in a function-like context, be advised that:
Macros are not type safe, and can be expanded regardless of whether they are syntatically correct - the compile phase will report errors resulting from macro expansion problems.
Macros can be used in context where you don't expect, resulting in proble...