Function objectMap

By analogy with how Array.prototype.map will map the elements of an array to transformed elements of an array of the same shape, objectMap will do likewise for the string-named own enumerable properties of an object.

Typical usage applies objectMap to a CopyRecord, i.e., an object for which passStyleOf(original) === 'copyRecord'. For these, none of the following edge cases arise. The result will be a CopyRecord with exactly the same property names, whose values are the mapped form of the original's values.

When the original is not a CopyRecord, some edge cases to be aware of

• No matter how mutable the original object, the returned object is hardened.
• Only the string-named enumerable own properties of the original are mapped. All other properties are ignored.
• If any of the original properties were accessors, Object.entries will cause its getter to be called and will use the resulting value.
• No matter whether the original property was an accessor, writable, or configurable, all the properties of the returned object will be non-writable, non-configurable, data properties.
• No matter what the original object may have inherited from, and no matter whether it was a special kind of object such as an array, the returned object will always be a plain object inheriting directly from Object.prototype and whose state is only these new mapped own properties.

With these differences, even if the original object was not a CopyRecord, if all the mapped values are Passable, then the returned object will be a CopyRecord.