forked from zhurui/management
149 lines
4.4 KiB
Markdown
149 lines
4.4 KiB
Markdown
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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)
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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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## Install
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Install with [npm](https://www.npmjs.com/):
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```sh
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$ npm install --save has-value
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```
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**Works for:**
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* booleans
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* functions
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* numbers
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* strings
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* nulls
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* object
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* arrays
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## Usage
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Works with property values (supports object-path notation, like `foo.bar`) or a single value:
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```js
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var hasValue = require('has-value');
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hasValue('foo');
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hasValue({foo: 'bar'}, 'foo');
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hasValue({a: {b: {c: 'foo'}}}, 'a.b.c');
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//=> true
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hasValue('');
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hasValue({foo: ''}, 'foo');
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//=> false
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hasValue(0);
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hasValue(1);
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hasValue({foo: 0}, 'foo');
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hasValue({foo: 1}, 'foo');
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hasValue({foo: null}, 'foo');
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hasValue({foo: {bar: 'a'}}}, 'foo');
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hasValue({foo: {bar: 'a'}}}, 'foo.bar');
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//=> true
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hasValue({foo: {}}}, 'foo');
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hasValue({foo: {bar: {}}}}, 'foo.bar');
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hasValue({foo: undefined}, 'foo');
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//=> false
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hasValue([]);
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hasValue([[]]);
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hasValue([[], []]);
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hasValue([undefined]);
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hasValue({foo: []}, 'foo');
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//=> false
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hasValue([0]);
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hasValue([null]);
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hasValue(['foo']);
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hasValue({foo: ['a']}, 'foo');
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//=> true
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hasValue(function() {})
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hasValue(function(foo) {})
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hasValue({foo: function(foo) {}}, 'foo');
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hasValue({foo: function() {}}, 'foo');
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//=> true
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hasValue(true);
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hasValue(false);
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hasValue({foo: true}, 'foo');
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hasValue({foo: false}, 'foo');
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//=> true
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```
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## isEmpty
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To do the opposite and test for empty values, do:
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```js
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function isEmpty(o) {
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return !hasValue.apply(hasValue, arguments);
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}
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```
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## Release history
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### v1.0.0
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* `zero` always returns true
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* `array` now recurses, so that an array of empty arrays will return `false`
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* `null` now returns true
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## About
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### Related projects
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* [define-property](https://www.npmjs.com/package/define-property): Define a non-enumerable property on an object. | [homepage](https://github.com/jonschlinkert/define-property "Define a non-enumerable property on an object.")
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* [get-value](https://www.npmjs.com/package/get-value): Use property paths (`a.b.c`) to get a nested value from an object. | [homepage](https://github.com/jonschlinkert/get-value "Use property paths (`a.b.c`) to get a nested value from an object.")
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* [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.")
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* [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.")
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### Contributing
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Pull requests and stars are always welcome. For bugs and feature requests, [please create an issue](../../issues/new).
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### Contributors
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| **Commits** | **Contributor** |
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| --- | --- |
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| 17 | [jonschlinkert](https://github.com/jonschlinkert) |
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| 2 | [rmharrison](https://github.com/rmharrison) |
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### Building docs
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_(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.)_
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To generate the readme, run the following command:
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```sh
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$ npm install -g verbose/verb#dev verb-generate-readme && verb
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```
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### Running tests
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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:
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```sh
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$ npm install && npm test
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```
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### Author
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**Jon Schlinkert**
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* [github/jonschlinkert](https://github.com/jonschlinkert)
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* [twitter/jonschlinkert](https://twitter.com/jonschlinkert)
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### License
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Copyright © 2017, [Jon Schlinkert](https://github.com/jonschlinkert).
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Released under the [MIT License](LICENSE).
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***
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_This file was generated by [verb-generate-readme](https://github.com/verbose/verb-generate-readme), v0.6.0, on May 19, 2017._
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