Core.Object provides utilities for working with objects as dictionaries and records.
Core.Object provides utilities for working with objects as dictionaries and records.
JS historically lacked data structures designed specifically for representing records and dictionaries, and objects just doubled as those for the common use cases. While JS has added Map and Set structures natively, using objects as records and dictionaries is still common place, and there aren't many tools to use them for those use cases natively.
For example, these objects are used as options for configuring
operations, like babylon's parse operation, or Node's readFile.
They're used to represent headers in most HTTP libraries, or to
represent environment variables in Node, etc.
Folktale's Core.Object primarily aims to provide common tools for using objects as dictionaries. In doing so, most of the operations in this module are only concerned about own, enumerable properties, and don't respect the original object's shape. That is, a transformation such as:
toPairs(fromPairs(object))
Doesn't return a value necessarily equivalent to object. Because
all transformations are pure, objects get a new identity, they also
lose all symbols and non-enumerable properties, as well as the
[[Prototype]] field.
Currently Core.Object provides operations for converting from and to objects, and transforming objects. These operations are categorised as follows:
Converting: Operations that convert the data in the object to other types.
Transforming: Operations that transform the data in the object, giving you a new object.
Constructs an object from an array of (key, value) pairs.
Returns pairs of (key, value) for all own enumerable properties in an object.
Returns the values for all own enumerable properties in an object.
Transforms own properties of an object using a mapping function.
Transforms values of an object with an unary function.
{
mapEntries: require('./map-entries'),
mapValues: require('./map-values'),
values: require('./values'),
toPairs: require('./to-pairs'),
fromPairs: require('./from-pairs')
}