Deep Get

Get a nested property value.

Installation

npm install @stdlib/utils-deep-get

Usage

var deepGet = require( '@stdlib/utils-deep-get' );

deepGet( obj, path[, options] )

Returns a nested property value.

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

var val = deepGet( obj, 'a.b.c' );
// returns 'd'

For paths including arrays, specify the numeric index.

var arr = [
    { 'a': [ {'x': 5} ] },
    { 'a': [ {'x': 10} ] }
];

var val = deepGet( arr, '1.a.0.x' );
// returns 10

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

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

var val = deepGet( obj, [ 'a', 'b', 'c' ] );
// returns 'd'

The function accepts the following options:

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

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

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

var val = deepGet( obj, 'a/b/c', {
    'sep': '/'
});
// returns 'd'

deepGet.factory( path[, options] )

Creates a reusable deep get function. The factory method ensures a deepGet function is configured identically by using the same set of provided options.

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

dget( obj )

Returns a nested property value.

var dget = deepGet.factory( 'a.b.c' );

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

var val = dget( obj );
// returns 'd'

Examples

var randu = require( '@stdlib/random-base-randu' );
var deepGet = require( '@stdlib/utils-deep-get' );

var data;
var keys;
var val;
var i;

data = new Array( 100 );
for ( i = 0; i < data.length; i++ ) {
    data[ i ] = {
        'x': Date.now(),
        'y': [ randu(), randu(), i ]
    };
}

keys = [ 0, 'y', 2 ];
for ( i = 0; i < data.length; i++ ) {
    keys[ 0 ] = i;
    val = deepGet( data, keys );
    console.log( val );
}

See Also

• @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.

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

License

See LICENSE.

Copyright

Copyright © 2016-2024. The Stdlib Authors.