# Object object operation

## Function

 The Object prototype function provides key-value enumeration, JSON stringification, deep copy, merge, filter, clipping and high-order traversal capabilities.

## API List

| API | Description |
| ------ | ------ |
| [Object.len](/en/docs/object/len) | Returns the number of key-value pairs of the object itself. |
| [Object.to_string](/en/docs/object/to_string) | Serialize an object to a JSON string. |
| [Object.keys](/en/docs/object/keys) | Returns an array of object key names. |
| [Object.values](/en/docs/object/values) | Returns an array of object values. |
| [Object.entries](/en/docs/object/entries) | Returns an array of entries in the form [key, value]. |
| [Object.reverse](/en/docs/object/reverse) | Returns a new object with the key order reversed. |
| [Object.concat](/en/docs/object/concat) | Consolidate one or more objects into a new object. |
| [Object.clone](/en/docs/object/clone) | Returns a deep copy of the object. |
| [Object.delete](/en/docs/object/delete) | Delete the specified key. |
| [Object.has_key](/en/docs/object/has_key) | Determine whether the specified key exists in the object. |
| [Object.get](/en/docs/object/get) | Read the specified key and return the default value if missing. |
| [Object.is_empty](/en/docs/object/is_empty) | Determine whether the object is empty. |
| [Object.from_entries](/en/docs/object/from_entries) | Create an object from an array of [key, value] entries. |
| [Object.each](/en/docs/object/each) | Traverse object key values and execute callbacks. |
| [Object.map](/en/docs/object/map) | Traverse the object and write the callback return value into the new object. |
| [Object.filter](/en/docs/object/filter) | Filter the key-value pairs that make the callback result true. |
| [Object.every](/en/docs/object/every) | Determine whether all key-value pairs make the callback result true. |
| [Object.some](/en/docs/object/some) | Determine whether there is a key-value pair for the callback result to be true. |
| [Object.find](/en/docs/object/find) | Returns the first value that makes the callback result true. |
| [Object.find_key](/en/docs/object/find_key) | Returns the first key for which the callback result is true. |
| [Object.update](/en/docs/object/update) | Merge one or more objects into the current object in place. |
| [Object.pick](/en/docs/object/pick) | Select a field by key name and return a new object. |
| [Object.omit](/en/docs/object/omit) | Exclude fields by keyname and return a new object. |
| [Object.clear](/en/docs/object/clear) | Clear the object and return the original object. |

## Examples

```bt
user = {name: 'BT', age: 1}
result = user.keys()

// Output: ["name","age"]
print result
```

## Notes

- Objects maintain insertion order.
- clone, reverse, concat, map, filter, pick, omit, from_entries return new objects; delete, update, clear will modify the original object.