objMerge

Merges any number of objects into one new object, going down through nested objects. When two sources carry the same key, the later one wins.

Two plain objects under the same key are merged into a new object, so neither source ends up shared with the result and neither is modified. Anything else — including arrays — is replaced whole by the later value. Lodash merges arrays index by index instead, which quietly keeps elements the caller meant to drop, so objMerge({ a: [1, 2, 3] }, { a: [9] }) returns { a: [9] } here and { a: [9, 2, 3] } in Lodash.

A key that only one source carries is copied over as it is, so a nested object under such a key is shared with that source, exactly like the JavaScript spread. Use objClone when a fully independent copy is needed.

nullNone is returned when no argument is given, or when any argument is not an object.

objMergeNewKey is the narrower relative: it only adds keys that are missing and never overwrites an existing value.

Parameters

Name	Type	Required	Default
objects	...object[]List<Map<String, dynamic>?>*dict	●	–
The objects to merge, in order. Later objects win. They are passed as separate arguments.The objects to merge, in order. Later objects win. They are passed as a single list.

Returns

object | null

Map<String, dynamic>?

dict | None

Examples

objMerge({ a: 1 }, { b: 2 }); // Returns { a: 1, b: 2 }
objMerge({ a: 1 }, { a: 2 }, { a: 3 }); // Returns { a: 3 }
objMerge({ a: { b: 1, c: 2 } }, { a: { c: 9, d: 3 } }); // Returns { a: { b: 1, c: 9, d: 3 } }
objMerge({ a: [1, 2, 3] }, { a: [9] }); // Returns { a: [9] }
objMerge({ a: 1 }, null); // Returns null

objMerge([{'a': 1}, {'b': 2}]); // Returns {'a': 1, 'b': 2}
objMerge([{'a': 1}, {'a': 2}, {'a': 3}]); // Returns {'a': 3}
objMerge([{'a': {'b': 1, 'c': 2}}, {'a': {'c': 9, 'd': 3}}]); // Returns {'a': {'b': 1, 'c': 9, 'd': 3}}
objMerge([{'a': [1, 2, 3]}, {'a': [9]}]); // Returns {'a': [9]}
objMerge([{'a': 1}, null]); // Returns null

objMerge({'a': 1}, {'b': 2})  # Returns {'a': 1, 'b': 2}
objMerge({'a': 1}, {'a': 2}, {'a': 3})  # Returns {'a': 3}
objMerge({'a': {'b': 1, 'c': 2}}, {'a': {'c': 9, 'd': 3}})  # Returns {'a': {'b': 1, 'c': 9, 'd': 3}}
objMerge({'a': [1, 2, 3]}, {'a': [9]})  # Returns {'a': [9]}
objMerge({'a': 1}, None)  # Returns None