Instancesfrom

Instancesfrom is a term used in software engineering to describe a pattern or utility that constructs a collection of object instances from a given source. The source can be a list of records, a JSON payload, a database result set, or a serialized representation, and the produced output is a collection of typed instances created by a factory or constructor function.

Definition and scope: The core idea is transforming raw data into domain objects by applying a mapping rule to each source item. A typical signature is instancesFrom(source, factory), where factory takes a source item and returns a new object instance. The function iterates over the source and collects the results in a new collection of the desired type.

Usage and examples: In pseudocode:

instancesFrom(data, item => new User(item.id, item.name, item.email))

or

instancesFrom(records, User.fromRecord)

Applications include deserialization of API payloads, data ingestion pipelines, test data generation, and ORM-like instantiation batches. The pattern helps centralize object creation logic and ensures consistent initialization across a dataset.

Variants and related concepts: The pattern is closely related to factories, mappers, and deserializers. Variants include instancesFromJson, instancesFromSchema, and instancesFromRecords, which may differ in input format or validation behavior.

See also: factory method, mapper, deserialization, data transformation, object construction.