Fn functions

> Functions (fn) that make your javascript code cleaner

    !Downloads


#### Use fn.one to set constants conditionally:
!image

Installation

The latest version is available at: https://www.npmjs.com/package/fn-code

Use your favorite package manager to install. For instance:

``bash
yarn add fn-code
`

Then import it:

`typescript
import fn from 'fn-code'
`

Importing as fn is the way I prefer to use it. But it's a matter of preference, you could either chose another name or deconstruct the functions:

`typescript
import cleanCode from 'fn-code'
import { one } from 'fn-code'
`

Why use these functions?

You like functional programming. You find yourself doing shenanigans to achieve your goals. Let's see:

$3

For example:

My const variable binomialName depends on the animal variable value.

You try something like:

`typescript
let binomialName = ''

if(animal === 'cat') binomialName = 'Felis catus'
if(animal === 'dog') binomialName = 'Canis familiaris'
`

But this is not what you want since binomialName name is not a const.

You try something like:

`typescript
const binomialName = (animal === 'cat') ? 'Felis catus' : 'Canis familiaris'
`

This is meets the const criteria. Now what if you would have a third species now (animal 'lion' for instance)?

`typescript
const binomialName = (animal === 'cat') ? 'Felis catus' : ((animal === 'lion') ? 'Panthera leo' : 'Canis familiaris')
`

Ughhh! This escalates badly. Also, the ternary operator is only clean when the third operand is the default value (and not another conditional).

So, you are clever and you make a function:

`typescript

const binomialName = ((animal) => {
switch (animal) {
case 'cat':
return 'Felis catus'
case 'lion':
return 'Panthera leo'
case 'dog':
return 'Canis familiaris'
}
})(animal)
`

This is better since we have const and switch. But passing those parameters to make the function pure still looks weird.

Usage

You can use fn-code npm package to:

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``typescript
import fn from 'fn-code'

const binomialName = fn.one(animal, {
'cat': 'Felis catus'
'lion': 'Panthera leo'
'dog': 'Canis familiaris'
})
``

But what if you want to have a default value for binomialName when no condition is met?
For that, you can use the third optional argument, passing { default: '' }

``typescript
import fn from 'fn-code'

const binomialName = fn.one(animal, {
'cat': 'Felis catus'
'lion': 'Panthera leo'
'dog': 'Canis familiaris'
}, { default: 'Species not found' })
``

Hold on. Not everything fits as an object key: you want to pass a regex or a more specific comparison than case == value..

No problem! You can define the switch as an array of case functions and values!

(These case functions must always return boolean)

``typescript
const binomialName = fn.one(animal, [
{
case: (str: string) => str.includes('cat'),
value: 'Felis catus'
},
{
case: (str: string) => str.includes('lion'),
value: 'Panthera leo'
},
{
case: (str: string) => str.includes('dog'),
value: 'Canis familiaris'
}
], { default: 'Species not found' })

``

Alternatively, if it feels more familiar you can use fn.switch instead, as it is an alias for fn.one.

$3

Other similar functions might be added to the module.

Testing

Run the test suit with yarn test`.

Contributing

If you want to contribute in any of theses ways:

- Give your ideas or feedback
- Question something
- Point out a problem or issue
- Enhance the code or its documentation
- Help in any other way

You can (and should) open an issue or even a pull request!

Thanks for your interest in contributing to this repo!

Author

Luiz Felipe Zarco (felipezarco@hotmail.com)

License

This code is licensed under the MIT License. See the LICENSE.md file for more info.