Join Eve Porcello for an in-depth discussion in this video Const keyword, part of Learning ECMAScript 6.
- Much like the let keyword, we can use const…as an alternative when declaring variables.…The const keyword is short for constant…and allows us to set constant variables…that shouldn't be reassigned.…On line six here, I'm going to create a constant variable…called birthYear and I'm going to set this equal to a year.…Beneath this, I'm going to create a variable called age…and here, I will use the current year…and subtract birthYear.…
Now, beneath this, I'm going to console.log(age).…So, when we run this in our browser…and take a look at it in the console,…we see that calculation is occurring correctly.…So, what happens if I try to reassign this?…Let's say, on line seven here, I create a variable…called birthYear and I set it equal to something else.…We'll soon see when we reload this…that we see a duplicate declaration error.…
const is working as we hoped…to protect the values of certain variables.…So, let's take this a step further.…I'm going to get rid of six through nine here…and we're going to create a function…
- What is ECMAScript?
- Transpiling ECMAScript with Babel and Babel-node
- Using the let and const keywords
- Creating strings with template strings
- Enhancing object literals
- Working with ES6 classes and class inheritance
Skill Level Beginner
Q: The Babel API is out of date. How do I proceed with the course?
A: We are updating the course. In the meantime, you can install the babel-cli package and then install the presets that you need to follow along with the tutorials.