$ gnpm install boolean
boolean converts lots of things to boolean.
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$ npm install boolean
First you need to add a reference to boolean in your application:
const { boolean, isBooleanable } = require('boolean');
If you use TypeScript, use the following code instead:
import { boolean, isBooleanable } from 'boolean';
To verify a value for its boolean value, call the boolean
function and provide the value in question as parameter:
console.log(boolean('true')); // => true
The boolean
function considers the following values to be equivalent to true
:
true
(boolean)'true'
(string)'TRUE'
(string)'t'
(string)'T'
(string)'yes'
(string)'YES'
(string)'y'
(string)'Y'
(string)'on'
(string)'ON'
(string)'1'
(string)1
(number)In addition to the primitive types mentioned above, boolean also supports their object wrappers Boolean
, String
, and Number
.
Please note that if you provide a string
or a String
object, it will be trimmed.
All other values, including undefined
and null
are considered to be false
.
From time to time, you may not want to directly convert a value to its boolean equivalent, but explicitly check whether it looks like a boolean. E.g., although boolean('F')
returns false
, the string F
at least looks like a boolean, in contrast to something such as 123
(for which boolean(123)
would also return false
).
To figure out whether a value can be considered to be a boolean, use the isBooleanable
function:
console.log(isBooleanable('true')); // => true
The isBooleanable
function considers all of the above mentioned values to be reasonable boolean values, and additionally, also the following ones:
false
(boolean)'false'
(string)'FALSE'
(string)'f'
(string)'F'
(string)'no'
(string)'NO'
(string)'n'
(string)'N'
(string)'off'
(string)'OFF'
(string)'0'
(string)0
(number)To run quality assurance for this module use roboter:
$ npx roboter
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