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Javascript Articles
Page 523 of 534
Safely setting object properties with dot notation strings in JavaScript
You can use lodash's set method to set properties at any level safely. Setting first-level properties are pretty straightforward. Nested property access is tricky and you should use a tested library like lodash for it.You can set a deeply nested object in the following way −Examplelet _ = require("lodash"); let obj = { a: { b: { foo: "test" }, c: 2 } }; _.set(obj, "a.b.foo", "test1"); _.set(obj, "a.c", { test2: "bar" }); console.log(obj);OutputThis will give the output −{ a: { b: { foo: 'test1' ...
Read MoreSafely Accessing Deeply Nested Values In JavaScript
You can use lodash's get method to get properties at any level safely. Getting first-level properties is pretty straightforward. Nested property access is tricky and you should use a tested library like lodash for it.You can access a deeply nested object in the following way −Examplelet _ = require("lodash"); let obj = { a: { b: { foo: "test" }, c: 2 } }; console.log(_.get(obj, "a.b.foo")); console.log(_.get(obj, "a.c")); console.log(_.get(obj, "a.test")); console.log(_.get(obj, "a.test.x"));OutputThis will give the output −test 2 undefined undefinedYou can also write your own ...
Read MoreQuery-string encoding of a Javascript Object
The query string is made up of query parameters and used to send data to the server. This part of the URL is optional. It needs to be constructed by the developer. This can be done using a native method called encodeURIComponent.The encodeURIComponent() function encodes a Uniform Resource Identifier (URI) component by replacing each instance of certain characters by one, two, three, or four escape sequences representing the UTF-8 encoding of the characterUsing the new ES6 format, objects can be query string encoded in the following way −Examplelet obj = { name: 'John', age: 25, city: 'Chicago' ...
Read MoreWhat are the differences between lodash and underscore?
lodash and underscore are both utility libraries that make JavaScript easier by providing utils that make working with arrays, numbers, objects, strings, etc. much easier. These libraries are great for −Iterating arrays, objects, & stringsManipulating & testing valuesCreating composite functionsThey are both functional libraries. Lo-Dash is a fork of Underscore, and still follows Underscore’s API enough to allow it to serve as a drop-in replacement. But under the hood, it’s been completely rewritten, and it’s also added a number of features and functions that Underscore does not provide.Lo-Dash was created to provide more consistent cross-environment iteration support for arrays, strings, ...
Read MoreWrite the dependencies of backbone.js in javascript?
The only hard dependency(without which backbone js won't work at all) is Underscore.js. Underscore is a JavaScript library that provides a whole mess of useful functional programming helpers without extending any built-in objects.There are other dependencies required as you proceed to use more advanced features of backbone.js. For example,Libraries for RESTful persistence(Backbone.sync)History support via Backbone.RouterDOM manipulation with Backbone.View or Jquery
Read MoreWhat is JSlint error "missing radix parameter" in JavaScript?
The parseInt function available in JavaScript has the following signature −parseInt(string, radix);Where the parameters are the following −string − The value to parse. If this argument is not a string, then it is converted to one using the ToString method. Leading whitespace in this argument is ignored.radix − An integer between 2 and 36 that represents the radix (the base in mathematical numeral systems) of the string.If the radix parameter is omitted, JavaScript assumes the following −If the string begins with "0x", the radix is 16 (hexadecimal)If the string begins with "0", the radix is 8 (octal). This feature is ...
Read MoreWhat is the difference between `new Object()` and object literal notation in JavaScript?
Both new Object() notation and Object literal({}) notations do the same thing. They initialize an object. However, the second notation can be a little different if you start adding properties to it.Examplelet a = { name: 'Ayush' }This initialization is equivalent to −let a = new Object(); a.name = 'Ayush'orlet a = {} a.name = 'Ayush'
Read MoreAdvanced JavaScript Backend Basics
JavaScript programming language that is usually used for web scripting. It is a lightweight, interpreted programming language. JavaScript is one of the most programming languages for web development. For running JavaScript each browser has its own engine which enables the proper functioning of JavaScript in the browser. Some common Browsers and their JavaScript engines are −Spider Monkey for firefoxV8 for Google ChromeJavaScript code for SafariChakra for Microsoft Internet Explorer/ edgeTo make JavaScript universe and stop a browser from describing their own scripts. There is a standard set for JavaScript which will be used throughout the browser. there is an Association ...
Read MoreHow to convert MySQL DATETIME value to JSON format in JavaScript?
To convert, use JSON.stringify(). Following is the code to convert MySQL DATETIME value to JSON format in JavaScript − var mySQLDateTime = new Date("Fri Sep 06 2019 22 −54 −48 "); var yearValue = mySQLDateTime.getFullYear(); var dateValue = mySQLDateTime.getDate(); var monthValue=mySQLDateTime.getMonth(); var hour=mySQLDateTime.getHours(); var minutes=mySQLDateTime.getMinutes(); var second=mySQLDateTime.getSeconds(); jsonObject={"year" −yearValue,"month" :monthValue,"DateValue" :dateValue,"Hour" :hour ,"Minutes" :minutes,"Second" :second}; var dateJsonObject = JSON.stringify(jsonObject); document.write(dateJsonObject); The screenshot of the code is as follows −This will produce the following output −{"year" :2019,"month" :8,"DateValue" :6,"Hour" :22,"Minutes" :54,"Second" :48}The snapshot of the output is as follows −
Read MoreHow to Validate your Website Code?
Website development included writing code in HTML, CSS, JavaScript and the platform you’ve chosen. Your website may look correct, responsive and developed with website standards, but it may have some internal issues.Tools are provided by W3C, to validate your website code:Validate HTML5Validator.nu is a validator, which validates HTML5, ARIA, SVG 1.1 and MathML 2.0. It checks the complete document and points out where the markup isn’t following the doctype.W3C Markup ValidatorIt checks the HTML doctype and the markup. This validator is for those who are using HTML4 or XHTML1.x doctype. It also validates HTML5, but Validator.nu is considered far better since ...
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