has-value

What is has-value?

The has-value npm package is used to check if a value exists, is not empty, or is not undefined. It is useful for validating data and ensuring that required fields are populated.

What are has-value's main functionalities?

Check if a value exists

This feature checks if a given value exists. In this example, the string 'Hello World' is checked, and since it is a non-empty string, the result is true.

const hasValue = require('has-value');
console.log(hasValue('Hello World')); // true

Check if an object property has a value

This feature checks if a specific property of an object has a value. In this example, the object has a property 'name' with a value 'John Doe', so the result is true.

const hasValue = require('has-value');
const obj = { name: 'John Doe' };
console.log(hasValue(obj, 'name')); // true

Check if an array has a value

This feature checks if an array has any values. In this example, the array [1, 2, 3] is checked, and since it contains elements, the result is true.

const hasValue = require('has-value');
const arr = [1, 2, 3];
console.log(hasValue(arr)); // true

Check if a nested object property has a value

This feature checks if a nested property within an object has a value. In this example, the nested property 'user.name' is checked, and since it has a value 'Jane Doe', the result is true.

const hasValue = require('has-value');
const nestedObj = { user: { name: 'Jane Doe' } };
console.log(hasValue(nestedObj, 'user.name')); // true

Other packages similar to has-value

lodash

Lodash is a popular utility library that provides a wide range of functions for manipulating arrays, objects, and other data types. It includes a method `_.has` to check if a property exists in an object, which is similar to the functionality provided by has-value.

underscore

Underscore is another utility library similar to Lodash. It provides a method `_.has` to check if an object contains a given property. While it does not specifically check for non-empty values, it can be used in combination with other methods to achieve similar results.

validator

Validator is a library for string validation and sanitization. It includes methods to check if a string is empty or not, which can be used to validate the presence of values in a similar way to has-value.

README

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

Contributing

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

Running Tests

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

Building docs

(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

Contributors

Commits	Contributor
32	jonschlinkert
2	rmharrison
1	wtgtybhertgeghgtwtg

Author

Jon Schlinkert

• LinkedIn Profile
• GitHub Profile
• Twitter Profile

License

Copyright © 2018, Jon Schlinkert. Released under the MIT License.

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This file was generated by verb-generate-readme, v0.6.0, on March 03, 2018.