has-value
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Returns true if a value exists, false if empty. Works with deeply nested values using object paths.
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# has-value [](https://www.npmjs.com/package/has-value) [](https://npmjs.org/package/has-value) [](https://npmjs.org/package/has-value) [](https://travis-ci.org/jonschlinkert/has-value)
> Returns true if a value exists, false if empty. Works with deeply nested values using object paths.
Please consider following this project's author, [Jon Schlinkert](https://github.com/jonschlinkert), and consider starring the project to show your :heart: and support.
## Install
Install with [npm](https://www.npmjs.com/):
```sh
$ npm install --save has-value
```
## Heads up!
Breaking changes in v2.0! See the [release history](#release-history) for details.
## Usage
```js
const has = require('has-value');
console.log(has()) //=> true
console.log(has('foo')) //=> true
```
**Works for:**
* booleans
* functions
* numbers
* strings
* nulls
* object
* arrays
**isEmpty**
To do the opposite and test for empty values, do:
```js
const isEmpty = (...args) => !has(...args);
```
## Supported types
### Arrays
```js
console.log(has({ foo: { bar: ['a'] } }, 'foo.bar')); //=> true
console.log(has({ foo: { bar: [0] } }, 'foo.bar')); //=> true
console.log(has({ foo: { bar: [[[]]] } }, 'foo.bar')); //=> false
console.log(has({ foo: { bar: [[], []] } }, 'foo.bar')); //=> false
console.log(has({ foo: { bar: [] } }, 'foo.bar')); //=> false
```
### Booleans
```js
console.log(has({ foo: { bar: true } }, 'foo.bar')); //=> true
console.log(has({ foo: { bar: false } }, 'foo.bar')); //=> true
```
### Buffers
```js
console.log(has({ foo: { bar: new Buffer() } }, 'foo.bar')); //=> false
console.log(has({ foo: { bar: new Buffer('foo') } }, 'foo.bar')); //=> true
```
### Dates
Dates are always true.
```js
console.log(has({ foo: { bar: new Date() } }, 'foo.bar')); //=> true
```
### Errors
Returns `false` if `err.message` is an empty string.
```js
console.log(has({ foo: { bar: new Error() } }, 'foo.bar')); //=> false
console.log(has({ foo: { bar: new Error('foo') } }, 'foo.bar')); //=> true
```
### Functions
Functions are always true.
```js
console.log(has({ foo: { bar: function(foo) {} } }, 'foo.bar')); //=> true
console.log(has({ foo: { bar: function() {} } }, 'foo.bar')); //=> true
```
### Maps
```js
console.log(has({ foo: { bar: new Map() } }, 'foo.bar')); //=> false
console.log(has({ foo: { bar: new Map([['foo', 'bar']]) } }, 'foo.bar')); //=> true
```
### Null
`null` is always true, as it's assumed that this is a user-defined value, versus `undefined` which is not.
```js
console.log(has({ foo: { bar: null } }, 'foo.bar')); //=> true
```
### Objects
```js
console.log(has({ foo: { bar: {} } }, 'foo.bar')); //=> false
console.log(has({ foo: { bar: { a: 'a' }} } }, 'foo.bar')); //=> true
console.log(has({ foo: { bar: { foo: undefined } } }, 'foo.bar')); //=> false
console.log(has({ foo: { bar: { foo: null } } }, 'foo.bar')); //=> true
```
### Numbers
```js
console.log(has({ foo: { bar: 1 } }, 'foo.bar')); //=> true
console.log(has({ foo: { bar: 0 } }, 'foo.bar')); //=> true
```
### Regular expressions
```js
console.log(has({ foo: { bar: new RegExp() } }, 'foo.bar')); //=> false
console.log(has({ foo: { bar: new RegExp('foo') } }, 'foo.bar')); //=> true
```
### Sets
```js
console.log(has({ foo: { bar: new Set() } }, 'foo.bar')); //=> false
console.log(has({ foo: { bar: new Set(['foo', 'bar']) } }, 'foo.bar')); //=> true
```
### Strings
```js
console.log(has({ foo: { bar: 'a' } }, 'foo.bar')); //=> true
console.log(has({ foo: { bar: '' } }, 'foo.bar')); //=> false
```
## Undefined
```js
console.log(has({ foo: { bar: } }, 'foo.bar')); //=> false
console.log(has({ foo: { bar: void 0 } }, 'foo.bar')); //=> false
console.log(has({ foo: { bar: undefined } }, 'foo.bar')); //=> false
```
## Release history
### v2.0.0
**Breaking changes**
* Now returns false if the first argument is not an object, function or array, and the second argument is not a string or array.
### v1.0.0
* `zero` always returns true
* `array` now recurses, so that an array of empty arrays will return `false`
* `null` now returns true
## About
<details>
<summary><strong>Contributing</strong></summary>
Pull requests and stars are always welcome. For bugs and feature requests, [please create an issue](../../issues/new).
</details>
<details>
<summary><strong>Running Tests</strong></summary>
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:
```sh
$ npm install && npm test
```
</details>
<details>
<summary><strong>Building docs</strong></summary>
_(This project's readme.md is generated by [verb](https://github.com/verbose/verb-generate-readme), please don't edit the readme directly. Any changes to the readme must be made in the [.verb.md](.verb.md) readme template.)_
To generate the readme, run the following command:
```sh
$ npm install -g verbose/verb#dev verb-generate-readme && verb
```
</details>
### Related projects
You might also be interested in these projects:
* [define-property](https://www.npmjs.com/package/define-property): Define a non-enumerable property on an object. Uses Reflect.defineProperty when available, otherwise Object.defineProperty. | [homepage](https://github.com/jonschlinkert/define-property "Define a non-enumerable property on an object. Uses Reflect.defineProperty when available, otherwise Object.defineProperty.")
* [get-value](https://www.npmjs.com/package/get-value): Use property paths like 'a.b.c' to get a nested value from an object. Even works… [more](https://github.com/jonschlinkert/get-value) | [homepage](https://github.com/jonschlinkert/get-value "Use property paths like 'a.b.c' to get a nested value from an object. Even works when keys have dots in them (no other dot-prop library can do this!).")
* [set-value](https://www.npmjs.com/package/set-value): Create nested values and any intermediaries using dot notation (`'a.b.c'`) paths. | [homepage](https://github.com/jonschlinkert/set-value "Create nested values and any intermediaries using dot notation (`'a.b.c'`) paths.")
* [unset-value](https://www.npmjs.com/package/unset-value): Delete nested properties from an object using dot notation. | [homepage](https://github.com/jonschlinkert/unset-value "Delete nested properties from an object using dot notation.")
### Contributors
| **Commits** | **Contributor** |
| --- | --- |
| 32 | [jonschlinkert](https://github.com/jonschlinkert) |
| 2 | [rmharrison](https://github.com/rmharrison) |
| 1 | [wtgtybhertgeghgtwtg](https://github.com/wtgtybhertgeghgtwtg) |
### Author
**Jon Schlinkert**
* [LinkedIn Profile](https://linkedin.com/in/jonschlinkert)
* [GitHub Profile](https://github.com/jonschlinkert)
* [Twitter Profile](https://twitter.com/jonschlinkert)
### License
Copyright © 2018, [Jon Schlinkert](https://github.com/jonschlinkert).
Released under the [MIT License](LICENSE).
***
_This file was generated by [verb-generate-readme](https://github.com/verbose/verb-generate-readme), v0.6.0, on March 03, 2018._