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authorruki <waruqi@gmail.com>2018-11-08 00:38:48 +0800
committerruki <waruqi@gmail.com>2018-11-07 21:53:09 +0800
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+# defined
+
+return the first argument that is `!== undefined`
+
+[![browser support](http://ci.testling.com/substack/defined.png)](http://ci.testling.com/substack/defined)
+
+[![build status](https://secure.travis-ci.org/substack/defined.png)](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