boolean
boolean converts lots of things to boolean.
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Installation
$ npm install boolean
Quick start
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
.
Figuring out whether a value can be considered to be boolean
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)
Running quality assurance
To run quality assurance for this module use roboter:
$ npx roboter