existjs
v2.1.0
Published
Check variable existence
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existjs
v2.1.0 ( last update: 20 mar 2018 )
Does the variable exist and what is its type? The easy way to know. Typescript included.
Install
npm
npm install existjs --save
Node.js
const { exist, or, ... } = require('existjs');
Typescript
import { exist, or, ... } from 'existjs';
Browser
<script src='/node_modules/existjs/dist/existjs-min.js'></script>
<script>
// How to use:
// existjs.exist();
// existjs.or();
// ...
</script>
exist()
Does the variable exist?
exist(null); // false
exist(undefined); // false
exist(NaN); // false
exist(0); // true
exist(''); // true
exist([]); // true
exist({}); // true
exist(false); // true
exist('hello'); // true
or()
It chooses first existing variable
var c = or(null, null, undefined, 72, 12, null, 'hi'); // c = 72
var c = or(undefined, 0, 2); // c = 0
Check types
isObject({ age: 99 }); // true
isNumber(122); // true
isString('deal with it'); // true
isArray([ 1, 2, 3 ]); // true
isFunction(function() {}); // true
isBoolean(false); // true