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Articles on Trending Technologies
Technical articles with clear explanations and examples
What are the Features of Perl Language?
Perl is a programming language developed by Larry Wall, specially designed for text processing. There are following great feature of Perl LanguagePerl takes the best features from other languages, such as C, awk, sed, sh, and BASIC, among others.Perl's database integration interface DBI supports third-party databases including Oracle, Sybase, Postgres, MySQL, and others.Perl works with HTML, XML, and other mark-up languages.Perl supports Unicode.Perl is Y2K compliant.Perl supports both procedural and object-oriented programming.Perl interfaces with external C/C++ libraries through XS or SWIG.Perl is extensible. There are over 20, 000 third party modules available from the Comprehensive Perl Archive Network (CPAN).The Perl ...
Read MoreWhy to Learn Perl?
Perl is a programming language developed by Larry Wall, specially designed for text processing. It stands for Practical Extraction and Report Language. It runs on a variety of platforms, such as Windows, Mac OS, and the various versions of UNIX Following great features make this language necessary for the Programmers to learn −Perl is a stable, cross-platform programming language.Though Perl is not officially an acronym few people used it as Practical Extraction and Report Language.It is used for mission-critical projects in the public and private sectors.Perl is an Open Source software, licensed under its Artistic License, or the GNU General ...
Read MoreWhat is the reason to choose jasmine over jest?
There is no solid reason to choose jasmine over jest. Both are excellent libraries that have been around for a while and have an opinionated way of doing things that are quite similar. Jest is built on top of jasmine.One reason why you might choose jasmine over jest is that it is faster. (https://github.com/facebook/jest/issues/6694)
Read MoreWhat is the use of sinon.js?
SinonJS provides stand-alone test spies, stubs and mocks. It is a library that we can use to create object mocks for unit testing.Spies − Fake functions that we can use to track executions.Stubs −Functions replacements from which we can return whatever we want or have our functions work in a way that suites us to be able to test multiple scenarios.Mocks −Fake methodsAll these objects help in unit testing our code.
Read MoreHow to create an object property from a variable value in JavaScript?
JS has 2 notations for creating object properties, the dot notation and bracket notation.To create an object property from a variable, you need to use the bracket notation in the following way −Exampleconst obj = {a: 'foo'} const prop = 'bar' // Set the property bar using the variable name prop obj[prop] = 'baz' console.log(obj);OutputThis will give the output −{ a: 'foo', bar: 'baz' }ES6 introduces computed property names, which allow you to do −Exampleconst prop = 'bar' const obj = { // Use a as key a: 'foo', // Use the value of prop ...
Read MoreHow to terminate javascript forEach()?
You can't break from the forEach method and it doesn't provide to escape the loop (other than throwing an exception).You can use other functions like _.find from lodash instead −_.find − it breaks out of the loop when the element is found. For example,Example_.find([1, 2, 3, 4], (element) => { // Check your condition here if (element === 2) { return true; } // Do what you want with the elements here // ... });Throw an exception from forEach. For example,Exampletry { [1, 2, 3, 4].forEach((element) => { // Check your condition here if (element === 2) { throw new Error(); } // Do what you want with the elements here // ... }) } catch (e) { // Do nothing. }
Read MoreHow can I trigger an onchange event manually in javascript?
You can dispatch events on individual elements using the dispatchEvent method. Let's say you have an element test with an onChange event −Event handler −document.querySelector('#test').addEventListener('change', () => console.log("Changed!"))Triggering the event manually −const e = new Event("change"); const element = document.querySelector('#test') element.dispatchEvent(e);This will log the following −Changed!
Read MoreHow to delete a localStorage item when the browser window/tab is closed?
To clear a localStorage data on browser close, you can use the window.onunload event to check for tab close.Let's say you have a local storage object called MyStorage as a global for the sake of this example. Then you can write an event handler −Examplewindow.onunload = () => { // Clear the local storage window.MyStorage.clear() }This will clear the local storage on the tab/window close.
Read MoreHow to check if element exists in the visible DOM?
We can use the Node.contains method to do this check. The Node.contains() method returns a Boolean value indicating whether a node is a descendant of a given node, i.e. the node itself, one of its direct children (childNodes), one of the children's direct children, and so on.ExampleFor example, you are looking for an element with id test, you can use the following −const elem = document.querySelector('#test'); console.log(document.body.contains(elem));This will log true or false based on whether the element is present in the visible DOM.
Read MoreIncrement a date in javascript without using any libraries?
To add one day to date in JS, the setDate function is the best way. You can create the following function on the Date prototype to add days to the date.ExampleDate.prototype.addDays = function(days) { let d = new Date(this.valueOf()); d.setDate(d.getDate() + days); return d; } let date = new Date(); console.log(date.addDays(1));This will log the next day.
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