Thread by @joelnet

🔥🔥🔥 The #1 Recursion (Syntax) Twitter Thread

This thread will demonstrate an easy way to write recursive functions

The recursion will so be compared to a for loop for familiarity

Tail Calls and Performance discussed later, Syntax Only!

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#javascript

Step 1: Create your iteration variable(s)

In recursion, it can be easier to set a default value. Pass `i` again when calling `loop` on the `return` line

#javascript #code #dev #es6

Step 2: Add a break condition

Like a for loop, add the break before you write your code. This will prevent infinite looping.

Notice how the for loop is a "continue" and the recursion uses a "break". That means the condition must be flipped for recursion

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Step 3: Increment the variable(s) `i`

Like the for loop, this is considered the base for recursion. This should be completed before writing your code.

Instead of `i++` (mutation), the increment happens in the `return loop(i + 1)`.

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Step 4: Inputs

A for loops inputs are available in the scope. A recursions inputs should be function arguments.

These "input" function arguments should be added to the left of the `i`

Remember to pass them in the `return`

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Step 5: Outputs

A for loop's output will mutate a variable in the scope

A recursive function will return a new value

The output should be added between the inputs and `i`

Be sure to add `output` to both `return` statements!

#javascript #nodejs #es6 #dev #code #development

Bonus: Getting Fancy

Functions can be expressed in many ways. This code shows the function written as a function expression.

The code is using `concat`, which is fine for small arrays and concise code, but won't work well for large arrays.

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Bonus: Going Fast

When concise code AND performance are important, consider using an immutable library

This will let you write immutable code in a way that is also has performance

#javascript #nodejs #code #dev #es6 #development

Code Pen: codepen.io/joelnet/pen/OJ…

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Font: FiraCode (with ligatures)
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