Deep Set

Deep set a nested property.

Usage

var deepSet = require( '@stdlib/utils/deep-set' );

deepSet( obj, path, value[, options] )

Deep set a nested property.

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

var bool = deepSet( obj, 'a.b.c', 'beep' );
/*
	{ 'a': { 'b': { 'c': 'beep' } } }
*/

If the function is able to deep set a nested property, the function returns true; otherwise, the function returns false.

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

bool = deepSet( obj, 'a.beep.c', 'boop' );
// returns false

bool = deepSet( null, 'a.beep.c', 'boop' );
// returns false

bool = deepSet( 'bap', 'a.beep.c', 'boop' );
// returns false

For paths including arrays, specify the numeric index.

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

var bool = deepSet( arr, '1.a.0.x', 25 );
/*
	[
		{ 'a': [ {'x': 5} ] },
		{ 'a': [ {'x': 25} ] }
	]
*/

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

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

var bool = deepSet( obj, ['a','b','c'], 'beep' );
/*
	{ 'a': { 'b': { 'c': 'beep' } } }
*/

If value is a function, the argument is treated as a callback and should return a value to set.

function set( val ) {
	var ch = val;
	for ( var i = 0; i < 4; i++ ) {
		val += ch;
	}
	return val;
}
var obj = { 'a': { 'b': { 'c': 'd' } } };

var bool = deepSet( obj, 'a.b.c', set );
/*
	{ 'a': { 'b': { 'c': 'ddddd' } } }
*/

The function accepts the following options:

• sep: key path separator. Default: '.'.
• create: boolean indicating whether to create a path if the key path does not already exist. Default: false.

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 bool = deepSet( obj, 'a/b/c', 'beep', {
	'sep': '/'	
});
/*
	{ 'a': { 'b': { 'c': 'beep' } } }
*/

To create a key path which does not already exist, set the create option to true.

var bool = deepSet( obj, 'a.e.c', 'boop', {
	'create': true	
});
/*
	{ 
		'a': { 
			'b': {
				'c': 'beep'
			}, 
			'e': {
				'c': 'boop'
			} 
		}
	}
*/

deepSet.factory( path[, options] )

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

var dset = deepSet.factory( 'a/b/c', {
	'create': true,
	'sep': '/'
});

dset( obj, value )

Deep sets a nested property.

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

var bool = dset( obj, 'beep' );
/*
	{ 'a': { 'b': { 'c': 'beep' } } }
*/

Examples

var randu = require( '@stdlib/math/base/random/randu' );
var deepSet = require( '@stdlib/utils/deep-set' );

var data;
var bool;
var keys;
var i;

function set( val ) {
	return val * 10;
}

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;
	bool = deepSet( data, keys, set );
	if ( !bool ) {
		console.error( 'Unable to deep set value.' );
	}
}
console.log( data );