feat: merge function

[stefan-gorules]

Summary

• Add merge function for combining arrays or objects
• Add mergeDeep function for recursively combining nested objects

merge

Combines an array of arrays or an array of objects into a single result.

Arrays — concatenates all arrays into one:

merge([[1, 2], [3, 4], [5]]) // [1, 2, 3, 4, 5]

Objects — combines all objects, last value wins for duplicate keys:

merge([{a: 1}, {b: 2}, {c: 3}]) // {a: 1, b: 2, c: 3}
merge([{a: 1, b: 2}, {b: 3, c: 4}]) // {a: 1, b: 3, c: 4}

mergeDeep

Recursively merges an array of objects. Unlike merge, nested objects are combined rather than replaced, and nested arrays are concatenated.

Nested objects — recursively merged:

mergeDeep([{a: {x: 1}}, {a: {y: 2}}]) // {a: {x: 1, y: 2}}
mergeDeep([{a: {b: {c: 1}}}, {a: {b: {d: 2}}}]) // {a: {b: {c: 1, d: 2}}}

Nested arrays — concatenated:

mergeDeep([{tags: [1, 2]}, {tags: [3, 4]}]) // {tags: [1, 2, 3, 4]}

Scalar values — last value wins:

mergeDeep([{a: 1}, {a: 2}]) // {a: 2}