Merge and extend objects.
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Merge and extend objects.
bash
npm install @stdlib/utils-mergescript tag without installation and bundlers, use the [ES Module][es-module] available on the [esm][esm-url] branch (see [README][esm-readme]).deno][deno-url] branch (see [README][deno-readme] for usage intructions).umd][umd-url] branch (see [README][umd-readme]).javascript
var merge = require( '@stdlib/utils-merge' );object.javascript
var target = {
'a': 'beep'
};
var source = {
'a': 'boop',
'b': 'bap'
};
var out = merge( target, source );
/* returns
{
'a': 'boop',
'b': 'bap'
}
*/objects.javascript
var target = {
'a': 'beep'
};
var source1 = {
'b': 'boop'
};
var source2 = {
'c': 'cat'
};
var out = merge( target, source1, source2 );
/* returns
{
'a': 'beep',
'b': 'boop',
'c': 'cat'
}
*/function for merging and extending objects.javascript
var opts = {
'level': 100,
'copy': true,
'override': true,
'extend': true
};
var m = merge.factory( opts );options:+infinity.boolean indicating whether to [deep copy][@stdlib/utils/copy] merged values. Deep copying prevents shared references and source object mutation. Default: true.true, source object values will always override target object values. If false, source values never override target values (useful for adding, but not overwriting, properties). To define a custom merge strategy, provide a function. Default: true.boolean indicating whether new properties can be added to the target object. If false, only shared properties are merged. Default: true.javascript
var m = merge.factory( {} );
var target = {
'a': {
'b': {
'c': 5
},
'd': 'beep'
}
};
var source = {
'a': {
'b': {
'c': 10
}
}
};
var out = m( target, source );
/* returns
{
'a': {
'b': {
'c': 10
},
'd': 'beep'
}
}
*/level option.javascript
var m = merge.factory({
'level': 2
});
var target = {
'1': {
'a': 'beep',
'2': {
'3': null,
'b': [ 5, 6, 7 ]
}
}
};
var source = {
'1': {
'b': 'boop',
'2': {
'3': [ 1, 2, 3 ]
}
}
};
var out = m( target, source );
/* returns
{
'1': {
'a': 'beep',
'b': 'boop',
'2': {
'3': [ 1, 2, 3 ]
}
}
}
*/javascript
var m = merge.factory( {} );
var target = {
'a': null
};
var source = {
'a': {
'b': [ 1, 2, 3 ]
}
};
var out = m( target, source );
console.log( out.a.b === source.a.b );
// => falsecopy option to false.javascript
var m = merge.factory({
'copy': false
});
var target = {};
var source = {
'a': [ 1, 2, 3 ]
};
var out = m( target, source );
var bool = ( out.a === source.a );
// returns trueoverride option to false.javascript
var m = merge.factory({
'override': false
});
var target = {
'a': 'beep',
'b': 'boop'
};
var source = {
'a': null,
'c': 'bop'
};
var out = m( target, source );
/* returns
{
'a': 'beep',
'b': 'boop',
'c': 'bop'
}
*/override option to a function.javascript
function strategy( a, b, key ) {
/* Parameters:
a => target value
b => source value
key => object key
*/
if ( key === 'a' ) {
return b;
}
if ( key === 'b' ) {
return a;
}
return 'bebop';
}
var m = merge.factory({
'override': strategy
});
var target = {
'a': 'beep',
'b': 'boop',
'c': 1234
};
var source = {
'a': null,
'b': {},
'c': 'bop'
};
var out = m( target, source );
/* returns
{
'a': null,
'b': 'boop',
'c': 'bebop'
}
*/object, set the extend option to false.javascript
var m = merge.factory({
'extend': false
});
var target = {
'a': 'beep',
'b': 'boop'
};
var source = {
'b': 'hello',
'c': 'world'
};
var out = m( target, source );
/* returns
{
'a': 'beep',
'b': 'hello'
}
*/object is mutated.javascript
var target = {
'a': 'beep'
};
var source = {
'b': 'boop'
};
var out = merge( target, source );
console.log( out === target );
// => true
console.log( target.b );
// => 'boop'object, provide an empty object as the first argument.javascript
var target = {
'a': 'beep'
};
var source = {
'b': 'boop'
};
var out = merge( {}, target, source );
console.log( out === target );
// => falseobjects are merged and extended. The following values/types are either [deep copied][@stdlib/utils/copy] or assigned:BooleanStringNumberDateRegExpArrayInt8ArrayUint8ArrayUint8ClampedArrayInit16ArrayUint16ArrayInt32ArrayUint32ArrayFloat32ArrayFloat64ArrayBuffer ([Node.js][node-buffer])SetMapErrorURIErrorReferenceErrorSyntaxErrorRangeErrorNumber, String, or Boolean objects are merged as [primitives][@stdlib/utils/copy].
