JarCastingfalsey 
Returns true if the given is falsey (according to JavaScript) or matches a 'falsey' keyword.
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Install
Install with npm:
$ npm install --save falsey
What is this?
This is intended to be a fun way of accepting alternatives to false or "no" in CLI prompts, web forms, etc. For example, you might want to allow users to define nil or nope to disable something.
Usage
const falsey = require('falsey');
console.log(falsey()); //=> true
console.log(falsey(false)); //=> true
console.log(falsey('nil')); //=> true
console.log(falsey('nope')); //=> true
console.log(falsey('yes')); //=> false
Examples
Any value that is not falsey (according to JavaScript) and is not in the list of falsey keywords will return false:
falsey('abc');
falsey(true);
falsey(1);
falsey('1');
falsey({});
falsey([]);
Any value that is falsey (according to JavaScript) or is in the list of falsey keywords will return true:
falsey(); //=> true
falsey(''); //=> true
falsey(0); //=> true
falsey(false); //=> true
falsey(NaN); //=> true
falsey(null); //=> true
falsey(undefined); //=> true
falsey(void 0); //=> true
Falsey keywords
If a value matches one of the built-in "falsey" keywords (all strings) it will return true:
0falsenadanilnaynahnegativenononenopenulnullnixnyetuh-uhvetozero
Customize falsey keywords
Pass an array of custom keywords that should return true when evaluated as falsey:
falsey('zilch', ['no', 'nope', 'nada', 'zilch']); //=> true
Disable built-in keywords by passing an empty array:
falsey('nil', []); //=> false
Extend built-in keywords
Built-in keywords are exposed on the .keywords property so that you may extend them with your own keywords:
falsey('zilch', falsey.keywords.concat(['zilch'])); //=> true
Release history
v1.0
Breaking changes
- objects will now always returns
false - more words were added to the built-in list of falsey keywords
About
Contributing
Pull requests and stars are always welcome. For bugs and feature requests, please create an issue.
Running Tests
Running and reviewing unit tests is a great way to get familiarized with a library and its API. You can install dependencies and run tests with the following command:
$ npm install && npm test
Building docs
(This project's readme.md is generated by verb, please don't edit the readme directly. Any changes to the readme must be made in the .verb.md readme template.)
To generate the readme, run the following command:
$ npm install -g verbose/verb#dev verb-generate-readme && verb
Related projects
You might also be interested in these projects:
- is-number: Returns true if the value is a number. comprehensive tests. | homepage
- is-primitive: Returns
trueif the value is a primitive. | homepage - isobject: Returns true if the value is an object and not an array or null. | homepage
- kind-of: Get the native type of a value. | homepage
Contributors
| Commits | Contributor |
|---|---|
| 12 | jonschlinkert |
| 9 | doowb |
| 3 | jesstelford |
Author
Jon Schlinkert
License
Copyright © 2018, Jon Schlinkert. Released under the MIT License.
This file was generated by verb-generate-readme, v0.6.0, on March 18, 2018.