@stdlib/assert-deep-has-own-property NPM

deepHasOwnProp

Test whether an object contains a nested key path.

Installation

npm install @stdlib/assert-deep-has-own-property

Usage

var deepHasOwnProp = require( '@stdlib/assert-deep-has-own-property' );

deepHasOwnProp( value, path[, options] )

Returns a boolean indicating if a value has a specified path.

var obj = { 'a': { 'b': { 'c': 'd' } } };

var bool = deepHasOwnProp( obj, 'a.b.c' );
// returns true

bool = deepHasOwnProp( obj, 'a.b.c.d.e' );
// returns false

If a key path includes an array, specify the numeric index.

var arr = [
    {
        'a': [
            {
                'b': [
                    { 'c': 'd' },
                    { 'e': 'f' }
                ]
            }
        ]
    }
];

var bool = deepHasOwnProp( arr, '0.a.0.b.0.c' );
// returns true

bool = deepHasOwnProp( arr, '0.a.1.b.0.c' );
// returns false

bool = deepHasOwnProp( arr, '0.a.0.b.1.c' );
// returns false

The key path may be specified as either a delimited string or a key array.

var obj = { 'a': { 'b': { 'c': 'd' } } };

var bool = deepHasOwnProp( obj, [ 'a', 'b', 'c' ] );
// returns true

The function accepts the following options:

sep: key path separator. Default: '.'.

By default, the function assumes . separated key values. To specify an alternative separator, set the sep option.

var obj = { 'a': { 'b': { 'c': 'd' } } };

var bool = deepHasOwnProp( obj, 'a/b/c', {
    'sep': '/'
});
// returns true

deepHasOwnProp.factory( path[, options] )

Returns a function which tests whether a value contains a nested key path.

var has = deepHasOwnProp.factory( 'a/b/c', {
    'sep': '/'
});

has( value )

Returns a boolean indicating whether a value contains a nested key path.

var has = deepHasOwnProp.factory( 'a.b.c' );

var obj = { 'a': { 'b': { 'c': 'd' } } };

var bool = has( obj );
// returns true

Notes

Only own properties are tested. Paths matching inherited properties are not considered.

function Foo() {
    this.a = 'b';
    return this;
}
Foo.prototype.c = 'd';

var foo = new Foo();

var bool = deepHasOwnProp( foo, 'a' );
// returns true

bool = deepHasOwnProp( foo, 'c' );
// returns false

When provided null or undefined, the function result is always false.

var bool = deepHasOwnProp( null, 'a.b.c' );
// returns false

bool = deepHasOwnProp( void 0, 'a.b.c' );
// returns false

Property values other than null or undefined are coerced to objects.

var obj = {
    'a': 'b'
};

var bool = deepHasOwnProp( obj, 'a.length' );
// returns true

Key path array elements are coerced to strings.

var obj = {
    'null': false
};
var bool = deepHasOwnProp( obj, [ null ] );
// returns true

obj = {
    '[object Object]': false
};
bool = deepHasOwnProp( obj, [ {} ] );
// returns true

Examples

var deepHasOwnProp = require( '@stdlib/assert-deep-has-own-property' );

var bool = deepHasOwnProp( { 'a': { 'b': { 'c': 'd' } } }, 'a.b.c' );
// returns true

bool = deepHasOwnProp( { 'a': { 'b': { 'c': 'd' } } }, [ 'a', 'b', 'c' ] );
// returns true

bool = deepHasOwnProp( { 'a': { 'b': { 'c': 'd' } } }, 'a/b/c', {
    'sep': '/'
});
// returns true

bool = deepHasOwnProp( { 'a': { 'b': { 'c': 'd' } } }, 'a.b.c.d' );
// returns false

bool = deepHasOwnProp( { 'a': [ { 'b': { 'c': 'd' } } ] }, [ 'a', '0', 'b', 'c', 'd' ] );
// returns false

bool = deepHasOwnProp( { 'a': { 'b': { 'c': 'd' } } }, 'a/b/c/d/e', {
    'sep': '/'
});
// returns false

// Create a customized function:
var has = deepHasOwnProp.factory( 'a_b_c', {
    'sep': '_'
});

bool = has( { 'a': { 'b': { 'c': 'd' } } } );
// returns true

bool = has( { 'a': [ { 'b': { 'c': 'd' } } ] } );
// returns false

Notice

This package is part of stdlib, a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.

For more information on the project, filing bug reports and feature requests, and guidance on how to develop stdlib, see the main project repository.