Here are my 7 simple tips to make your JavaScript easier to read.

Does your JavaScript code start off being easy to read, but over time turns into spaghetti?

Here are my 7 simple tips to make your JavaScript easier to read. 

1. Avoid indirection. 

- Your functions should return results instead of mutating their parameters. 

- Prefer promises over callbacks. 

Your code should flow in a single direction, consistently and predictably.


2. Use guard clauses to reduce nesting in conditions. 

When you return inside of the if-statement, everything after that statement is basically an `else` clause. Take advantage of it to reduce excessive nesting. 

Tip: don't forget you can invert conditions by negating them.

3. Prevent ambiguous states. 

When you model your state as a state machine, it becomes unambiguous, thus easier to read. 

For example, if you have states such as isLoading, isLoaded, isSaving, and isError, they can't all be true at once. Use a string literal for that.


4. Handle promise errors. 

We tend to forget that things can fail for random reasons. Wrap your async calls with try/catch blocks and handle their failures properly.

5. Replace switch/if-statements with object literal lookup. 

When you use an if-statement to determine the value to use instead of directing control flow, the object literal lookup may be a better choice. 

Tip: you can put functions in the object and direct control flow as well.

6. Prefer declarative APIs over "speed optimizations". 

JavaScript arrays have declarative functions like `map()`, `filter()` or `find()`. You should use them instead of writing imperative, hard-to-read code, even when you can cram it all into a single for-loop.

7. Name your function arguments. 

When your function asks for more than 1-2 arguments, it becomes hard to follow which is which. Prefer a "config" object to provide names for function parameters. 

Tip: when you use an object, some parameters can also be optional.



Source:
Vincas Stonys
@VincasStonys