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How to check for an undefined or null variable in JavaScript?
...quality will also return true for undefined.
if (window.variable == null) alert('variable is null or undefined');
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Script Tag - async & defer
... a couple of questions about the attributes async & defer for the <script> tag which to my understanding only work in HTML5 browsers.
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JavaScript for…in vs for
...hen using this function.
Example:
$(['a','b','c']).each(function() {
alert(this);
});
//Outputs "a" then "b" then "c"
The downside of using this is that if you're doing some non UI logic, your functions will be less portable to other frameworks. The each() function is probably best reserved ...
When to catch java.lang.Error?
... i'd suspect its better in those cases to fail the daemon with proper alerts then to have the possibility of it staying alive as some etherial ghost on a failed jvm where it might give the false pretext that it is really alive and doing something
– Andrew Norman
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React JSX: selecting “selected” on selected option
...tState({value: event.target.value});
handleSubmit = (event) => {
alert('Your favorite flavor is: ' + this.state.value);
event.preventDefault();
}
render() {
return (
<form onSubmit={this.handleSubmit}>
<label>
Pick your favorite flavor:
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Reliable way for a Bash script to get the full path to itself [duplicate]
I have a Bash script that needs to know its full path. I'm trying to find a broadly-compatible way of doing that without ending up with relative or funky-looking paths. I only need to support Bash, not sh, csh, etc.
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Formatting code snippets for blogging on Blogger [closed]
... Can anyone confirm if this still works? I tried pasting the script tag just before the </head> section and added the pre tag around my code as well. No change though.
– arviman
Nov 2 '11 at 4:21
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Determining whether jQuery has not found any element
...e { /* code if not found */ }
You're getting an object returned from that alert because jQuery (almost) always returns the "jQuery object" when you use it, which is a wrapper for the elements jQuery's found that permits method chaining.
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this.setState isn't merging states as I would expect
...gt; _.merge({}, previousState, { selected: { name: "Barfood"} }), () => alert(this.state.selected));
I used merge because extend discards the other properties otherwise.
React Immutability example:
import update from "react-addons-update";
this.setState((previousState) => update(previousS...
In a Bash script, how can I exit the entire script if a certain condition occurs?
I'm writing a script in Bash to test some code. However, it seems silly to run the tests if compiling the code fails in the first place, in which case I'll just abort the tests.
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