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July 19, 2020 02:08 am GMT

More readable conditional with Array.includes()

Do you know the function Array.includes() of the JavaScript? This function was specified in ES7 and is capable of making a conditional much more readable.

This function determines is the parameter is contained in the array.

const numbers = [1, 2, 3, 4]const strings = ['Gabriel', 'Rufino']numbers.includes(3) // truenumbers.includes(6) // falsestrings.includes('Rufino') // truestrings.includes('Fernando') // false

Knowing this function, you can now write more readable conditionals that compare a variable with many possibilities by replacing large chains of or operator (||) with Array.includes() using a variable as the parameter. See the example:

Using `or` operator

function get(request, response) {  const access = request.access  if (access === 'maintainer' || access === 'admin' || access === 'developer') {    return response.json({ allowed: true })  } else {    return response.json({ allowed: false })  }}

Using `Array.includes()`

function get(request, response) {  const access = request.access  if (['maintainer', 'admin', 'developer'].includes(access)) {    return response.json({ allowed: true })  } else {    return response.json({ allowed: false })  }}

Works with `NaN`

NaN === NaN // false[1, 2, 3, NaN].includes(NaN) // true

Thanks!

Original Link: https://dev.to/gabrielrufino/more-readable-conditional-with-array-includes-2m3j

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