JavaScript Tutorials
JavaScript variables are dynamically typed. That means variables do not have any fixed type, we don’t have to define/set type explicitly. The type of the variable can change during execution. For example, a variable can contain a string and then later it can contain a number, and later some other data.
Here is the rule of thumb for variables passed by value vs reference- all primitive type variables(Number, String, Boolean, Symbol, etc.) are passed by value and all non-primitive type variables(object, array, etc.) are passed by reference.
Hoisting deals with variables or function usage before its definition. Hoisting happens for the variables defined with “var”. For the variables defined with “let” or constants defined with “const”, hoisting will not happen. Hoisting happens for both variables and functions.
Understanding the scope of a variable is really a critical part of learning JavaScript. By using the variable in a place where it is not available will throw errors and/or introduce bugs. Scope of the variable defines- in which part of the code the variable will be available.
A variable is a named identifier of a storage/space in the memory. In this article we are discussing JavaScript naming process and the process of definable a variable.
Using tagged template literals we can parse the template string and then we can perform any operation on the parts of the template literal if required.
If you are designing some event-heavy component using JavaScript, then the propagation of the event becomes very critical. Any event like “click”, “hover” etc. has 2 ways of traveling through the components. To understand the capturing and bubbling, we need to understand the params of “addEventListener” method of EventTarget. Here is the signature of “addEventListener”.
“use strict” directive enables a strict operating context/mode for the code. This helps us to identify potential exceptions and makes debugging easier. In strict mode, we are notified about code that would trigger some weird behavior or fail silently. To enable the strict mode for the whole script, add the string “use strict” at the top of the script.
The data you are trying to parse in JavaScript is already a JavaScript Object. When the JSON.parse(data) tries to parse a string to JSON, it expects a string. And it is getting a JSON object already, which has the “o” (from the “object”), so JavaScript can not parse it.
