The binary object has three required properties
We refer to values of these types as "primitive values". Boolean represents a logical entity and can have two values: The Null type has exactly one value: See null and Null for more details.
An escape character can be chosen, etc. All of this requires conventions and creates an unnecessary maintenance burden. Use strings for textual data.
When representing complex data, parse strings and use the appropriate abstraction. A Symbol is a unique and immutable primitive value and may be used as the key of an Object property see below. In some programming languages, Symbols are called atoms.
With the object literal syntaxa limited set of properties are initialized; then properties can be added and removed. Property values can be values of any type, including other objects, which enables building complex data structures. Properties are identified using key values. A key value is either a String or a Symbol value. There are two types of object properties which have certain attributes: The data property and the accessor property.
Additionally, arrays inherit from Array. For example, indexOf searching a value in the array or push adding an element to the arrayetc. This makes Arrays a perfect candidate to represent lists or sets. The following table helps you to find the equivalent C data types:. The difference between Maps and WeakMaps is that in the former, object keys can be enumerated over. This allows garbage collection optimizations in the latter case.
However, since objects cannot be compared in the sense of "less than" for instancelook-up performance would necessarily be linear.
Native implementations of them including WeakMaps can have look-up performance that is approximately logarithmic to constant time. This has the downside that the data is available to any script running in the same context. Maps and WeakMaps make it easy to privately bind data to an object. JSON builds universal data structures.
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If truethe property will be enumerated in for See also Enumerability and ownership of properties. If falsethe property can't be deleted and attributes other than [[Value]] and [[Writable]] can't be changed.
The function is called with an empty argument list and retrieves the property value whenever a get access to the value is performed. The function is called with an argument that contains the assigned value and is executed whenever a specified property is attempted to be changed.