Has-value NPM | npm.io

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, and consider starring the project to show your :heart: and support.

Install

Install with npm:

$ npm install --save has-value

Heads up!

Breaking changes in v2.0! See the release history for details.

Usage

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:

const isEmpty = (...args) => !has(...args);

Supported types

Arrays

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

console.log(has({ foo: { bar: true } }, 'foo.bar'));  //=> true
console.log(has({ foo: { bar: false } }, 'foo.bar')); //=> true

Buffers

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.

console.log(has({ foo: { bar: new Date() } }, 'foo.bar')); //=> true

Errors

Returns false if err.message is an empty string.

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.

console.log(has({ foo: { bar: function(foo) {} } }, 'foo.bar')); //=> true
console.log(has({ foo: { bar: function() {} } }, 'foo.bar'));    //=> true

Maps

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.

console.log(has({ foo: { bar: null } }, 'foo.bar')); //=> true

Objects

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

console.log(has({ foo: { bar: 1 } }, 'foo.bar')); //=> true
console.log(has({ foo: { bar: 0 } }, 'foo.bar')); //=> true

Regular expressions

console.log(has({ foo: { bar: new RegExp() } }, 'foo.bar'));      //=> false
console.log(has({ foo: { bar: new RegExp('foo') } }, 'foo.bar')); //=> true

Sets

console.log(has({ foo: { bar: new Set() } }, 'foo.bar'));               //=> false
console.log(has({ foo: { bar: new Set(['foo', 'bar']) } }, 'foo.bar')); //=> true

Strings

console.log(has({ foo: { bar: 'a' } }, 'foo.bar')); //=> true
console.log(has({ foo: { bar: '' } }, 'foo.bar'));  //=> false

Undefined

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

Pull requests and stars are always welcome. For bugs and feature requests, please create an issue.

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:

$ npm install && npm test

(This project's readme.md is generated by verb, please don't edit the readme directly. Any changes to the readme must be made in the .verb.md readme template.)

To generate the readme, run the following command:

$ npm install -g verbose/verb#dev verb-generate-readme && verb

Related projects

You might also be interested in these projects:

define-property: Define a non-enumerable property on an object. Uses Reflect.defineProperty when available, otherwise Object.defineProperty. | homepage
get-value: Use property paths like 'a.b.c' to get a nested value from an object. Even works… more | homepage
set-value: Create nested values and any intermediaries using dot notation ('a.b.c') paths. | homepage
unset-value: Delete nested properties from an object using dot notation. | homepage