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What is the JavaScript version of sleep()?
In JavaScript version of sleep() function sleeps a specified amount of time. It’s sometimes useful when you need to pause the execution of your program for a certain amount of time.
Here are two JavaScript version sleep() functions that can help you with this:
- setTimeout(), which creates a scheduled task that executes at a specific date and time, has elapsed in.
- setInterval(), which creates an event loop that repeats indefinitely.
What’s the equivalent of Java’s Thread.sleep() in JavaScript?
Thread.sleep() is a function in Java that allows you to pause execution for a specified amount of time. In JavaScript, the equivalent would be
setTimeout(function () { //do something }, 1000).
This will execute the function after one second has passed.
What’s the best way to validate an email address in JavaScript?
One way to validate an email address in JavaScript is by looping through the string and checking for a substring in that string.
- The first step is to create a variable, for example, email, which will store the string that should be checked for a substring.
- Then you can use substr() to take out a certain number of characters from the end of an email, so you’ll know if there are any numbers in it or not.
- Before you start to loop through the string, make sure to convert it into an array using String().
Why doesn’t JavaScript support multithreading?
JavaScript has no multithreading capabilities. This means that your code will always execute in a single thread at a time. In other languages, such as Java, Python, and C#.
It’s easier to create multithreaded applications because the CPU can run multiple processes simultaneously.
For example, if you have an application that is composed of many processes, then one process would be responsible for handling requests while another process handles updating a database.
If JavaScript did have multithreading capabilities, there would be more potential for concurrency and parallelism in the language itself.
How do JavaScript closures work?
The closure allows you to use an object’s properties without explicitly setting them. The closure is a very powerful feature of JavaScript, but it can also create some problems.
This code will print “Hello world!” every time it’s run because the function created by the closure is referencing the global variable “world”.
var message = function() {
wholeblogs.com
};
Output
How to remove properties from objects (JavaScript)
To remove properties from objects in JavaScript, you can use the delete operator.
For example, let’s say we have an object that has a property called “name” and we want to remove it.
var myVar = { name : "John Smith" }
myVar . deleteProperty ( 'name' );
myVar . name // John Smith
Output
- If you find yourself needing to know if a string contains a substring, then you would need to loop through the entire string and check each character.
- This would require checking each character of the string to see if it has the substring.
- If you’re iterating through strings of different lengths, this can be difficult because you won’t know if your loop will iterate through all of them or just a portion before stopping.
How do you get a timestamp in JavaScript?
There are two ways to get a timestamp in JavaScript: using the date() function or using the Date class.
How do I include a JavaScript file in another JavaScript file?
You can include a JavaScript file within another JavaScript file by adding the following line of code:
(['lib/dependency1', 'lib/dependency2'], function (d1, d2) { //Your actual script goes here.
//The dependent scripts will be fetched if necessary.
return libraryObject; //For example, jQuery object
What does “use strict” do in JavaScript, and what is the reasoning behind it?
The function useStrict() is an event listener that triggers when the browser encounters a “use strict” declaration. This will cause some changes to be made in the code and can help avoid any issues later on.
For instance, in this loop you’ve used the string “abcdefghijklmnopqrstuvwxyz” as opposed to “abcdefghijklmnopqrstu”, which would have made it much easier to compare its length with 5.
var str = 'abcdefghijklmnopqrstuvwxyz';
var length = str.length;
while (str !== null)
{ if (str === 'a') { console.log('found a'); }
else if (str === 'b') { console.log('found b'); }
else if (str === 'c') { console.log('found c'); }
else if (str === 'd') { console.log('found d'); }
else if (str === 'e') { console.log('found e'); }
else if (str === 'f') { console.log('found f'); }
else if (str === 'g') { console.log('found g'); }
else if (str === 'h') { console.log('found h'); }
else if (str === 'i') { console.log('found i'); }
else if (str === 'j') { console.log }
How is indexedDB conceptually different from HTML5 local storage?
IndexedDB is a JavaScript API that allows applications to store data locally. It provides a way to store key-value pairs in an IndexedDb object, which can be accessed by multiple clients simultaneously.
IndexedDB stores data on the client’s computer, not on the server.
HTML5 local storage is like IndexedDB in that it offers similar functionality and has no central point of access.
However, HTML5 local storage allows only one client to access the data at a time while IndexedDB allows many simultaneous users to access it.