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How to access component methods from “outside” in ReactJS?
...
class Parent extends React.Class {
constructor(props) {
this._child = React.createRef();
}
componentDidMount() {
console.log(this._child.current.someMethod()); // Prints 'bar'
}
render() {
return (
<div>
<Child ref=...
How to take screenshot of a div with JavaScript?
...
When the quiz is finished, do this:
var c = document.getElementById('the_canvas_element_id');
var t = c.getContext('2d');
/* then use the canvas 2D drawing functions to add text, etc. for the result */
When the user clicks "Capture", do this:
window.open('', document.getElementById('the_canvas...
How can I check if a file exists in Perl?
...mething exists at given path using the -e file-test operator.
print "$base_path exists!\n" if -e $base_path;
However, this test is probably broader than you intend. The code above will generate output if a plain file exists at that path, but it will also fire for a directory, a named pipe, a syml...
Facebook share link without JavaScript
...se
<a href="https://www.facebook.com/sharer/sharer.php?u=#url" target="_blank">Share</a>
Currently there is no sharing option without passing current url as a parameter. You can use an indirect way to achieve this.
Create a server side page for example: "/sharer.aspx"
Link this page...
How do I implement a callback in PHP?
...Heukelom
38.9k5555 gold badges167167 silver badges283283 bronze badges
1
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A monad is just a monoid in the category of endofunctors, what's the problem?
...of sets. You can read more about that here: en.wikipedia.org/wiki/Cartesian_product, but the basic idea is that an element of S × T is a pair (s, t), where s ∈ S and t ∈ T. So the signature of the monoidal product • : S × S -> S in this context simply means a function that takes 2 element...
Queries vs. Filters
... query
Query hello sam (using keyword must)
curl localhost:9200/myindex/_search?pretty -d '
{
"query": { "bool": { "must": { "match": { "msg": "hello sam" }}}}
}'
Document "Hello world! I am Sam." is assigned a higher score than "Hello world!", because the former matches both words in the qu...
Sorting data based on second column of a file
...000/svg\"\u003e\u003cpath d=\"M46.1709 9.17788C46.1709 8.26454 46.2665 7.94324 47.1084 7.58816C47.4091 7.46349 47.7169 7.36433 48.0099 7.26993C48.9099 6.97997 49.672 6.73443 49.672 5.93063C49.672 5.22043 48.9832 4.61182 48.1414 4.61182C47.4335 4.61182 46.7256 4.91628 46.0943 5.50789C45.7307 4.9328 4...
How to add extension methods to Enums
...on d = 0;
– Graham
Mar 30 '16 at 15:32
17
Given that enums are classes no they aren't classes.
...
How to create a .NET DateTime from ISO 8601 format
... Z actually stands for Zulu time or UTC. en.wikipedia.org/wiki/ISO_8601#UTC
– Peter Stephens
Jun 22 '11 at 19:22
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