This chapter (and the rest of the module) will focus on ES6 Arrow Functions assigned to constant variables. There are a few reasons for this:
- The syntax of assigning a function to a variable makes it clear from the
beginning that functions are just values, which is helpful for understanding
callbacks later on.
function name() {}syntax can make this less obvious. - Using a constant variable means you cannot accidentally assign a different value to the variable that stores your function. There's a whole type of bug you don't need to worry about!
- Having one way to declare a function makes it easier to focus on the basics.
Using
functionfunctions opens the door to many ways of declaring a function: named declarations, anonymous function expressions, named function expressions. - Function Hoisting is a possibly confusing behavior that can distract from focusing on how functions work, and how to use them in a program. Arrow functions assigned to constant variables are not hoisted, so no worries there! You can learn about this later.
Learn how to read, visualize, trace, test and debug functions in JavaScript.
Learn how to use default parameters and the JSDoc convention to clearly describe a function for other developers: its arguments, return value and behavior.
Study a few examples and practice using your browser's devtools to look inside the JavaScript execution environment and understand how nested function calls create a callstack.
Build on what you learned in The Callstack to understand 3 scoping mechanisms that can be used inside a function to assign values to your variables.