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.

Install

Install with npm:

$ npm install has-value --save

Works for:

• booleans
• functions
• numbers (pass true as the last arg to treat zero as a value instead of falsey)
• strings
• nulls
• object
• arrays

Usage

Works with nested object paths or a single value:

var hasValue = require('has-value');

hasValue({a: {b: {c: 'foo'}}} 'a.b.c');
//=> true

hasValue('a');
//=> true

hasValue('');
//=> false

hasValue(1);
//=> true

hasValue(0);
//=> false

hasValue(0, true); // pass `true` as the last arg to treat zero as a value
//=> true

hasValue({a: 'a'}});
//=> true

hasValue({}});
//=> false

hasValue(['a']);
//=> true

hasValue([]);
//=> false

hasValue(function(foo) {}); // function length/arity
//=> true

hasValue(function() {});
//=> false

hasValue(true);
hasValue(false);
//=> true

isEmpty

To do the opposite and test for empty values, do:

function isEmpty(o, isZero) {
  return !hasValue.apply(hasValue, arguments);
}

Related projects

You might also be interested in these projects:

• get-object: Get a property from an object using dot (object path) notation. | homepage
• get-property: Get a nested property or its value from an object using simple a.b.c paths. | homepage
• get-value: Use property paths (a.b.c) to get a nested value from an object. | homepage
• set-value: Create nested values and any intermediaries using dot notation ('a.b.c') paths. | homepage

Contributing

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

Building docs

Generate readme and API documentation with verb:

$ npm install verb && npm run docs

Or, if verb is installed globally:

$ verb

Running tests

Install dev dependencies:

$ npm install -d && npm test

Author

Jon Schlinkert

• github/jonschlinkert
• twitter/jonschlinkert

License

Copyright © 2016, Jon Schlinkert. Released under the MIT license.

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This file was generated by verb, v, on March 27, 2016.