🔎 Intro
This post covers the basics of JavaScript together with the new concepts and lessons learned during this part of the course.
💡 New concepts
Variables
- const:
The const declaration creates a read-only reference to a value. It does not mean the value it holds is immutable, just that the variable identifier cannot be reassigned. - let:
The let statement declares a block-scoped local variable, optionally initializing it to a value.
Arrays
- Concat():
The concat() method is used to merge two or more arrays. This method does not change the existing arrays, but instead returns a new array. - Destructuring assignment:
The destructuring assignment syntax is a JavaScript expression that makes it possible to unpack values from arrays, or properties from objects, into distinct variables.
Objects
- Object literal:
An object literal is a list of zero or more pairs of property names and associated values of an object, enclosed in curly braces ({}). - Object methods and “this”:
A method is a function which is a property of an object. It is called using the syntax objectName.methodName(). In a method, this refers to the owner object. In other words, this.firstName means the firstName property of this object. More details - Bind:
The bind() method creates a new function that, when called, has its this keyword set to the provided value, with a given sequence of arguments preceding any provided when the new function is called. More details
📚 Lessons learned
- There are many similarities between JavaScript and Python, such as the syntax of for loop, functions like
map,reduce, etc. However, there are also many differences between them, such as the way of declaring variables, the way of creating functions, etc. In short, the syntax of JavaScript is slightly a confusing thing for me so far when, unfortunately, everytime Python comes to my mind first. At the moment they’re like two angles fighting in my head…😂
📝 Course exercise
- A simple React app that displays some contents of courses. Link to the repo