You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
53 lines
1.1 KiB
53 lines
1.1 KiB
# defined |
|
|
|
return the first argument that is `!== undefined` |
|
|
|
[](http://ci.testling.com/substack/defined) |
|
|
|
[](http://travis-ci.org/substack/defined) |
|
|
|
Most of the time when I chain together `||`s, I actually just want the first |
|
item that is not `undefined`, not the first non-falsy item. |
|
|
|
This module is like the defined-or (`//`) operator in perl 5.10+. |
|
|
|
# example |
|
|
|
``` js |
|
var defined = require('defined'); |
|
var opts = { y : false, w : 4 }; |
|
var x = defined(opts.x, opts.y, opts.w, 100); |
|
console.log(x); |
|
``` |
|
|
|
``` |
|
$ node example/defined.js |
|
false |
|
``` |
|
|
|
The return value is `false` because `false` is the first item that is |
|
`!== undefined`. |
|
|
|
# methods |
|
|
|
``` js |
|
var defined = require('defined') |
|
``` |
|
|
|
## var x = defined(a, b, c...) |
|
|
|
Return the first item in the argument list `a, b, c...` that is `!== undefined`. |
|
|
|
If all the items are `=== undefined`, return undefined. |
|
|
|
# install |
|
|
|
With [npm](https://npmjs.org) do: |
|
|
|
``` |
|
npm install defined |
|
``` |
|
|
|
# license |
|
|
|
MIT
|
|
|