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

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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

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See Also

• @stdlib/assert-deep-has-property: test whether an object contains a nested key path, either own or inherited.
• @stdlib/assert-has-own-property: test if an object has a specified property.
• @stdlib/utils-deep-get: get a nested property value.
• @stdlib/utils-deep-pluck: extract a nested property value from each element of an object array.
• @stdlib/utils-deep-set: set a nested property value.

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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.

Community

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License

See LICENSE.

Copyright

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