Destructuring assignment
Destructuring assignment is syntax that decomposes a structured value according to a pattern and binds selected components to names.
Clojure: The Essential Reference
Associative destructuring binds values from key-value collections to names according to keys specified in a binding form.
- How it is used
- Binds selected map values to local names in `let` and function parameters, avoiding repeated key lookups.
- How deep it goes
- Defines key-based forms, defaults, aliasing, and nesting, then shows their translation into ordinary binding pairs.
- Examples
- Uses a map with a missing key and an explicit `nil`, plus a function parameter containing nested map and sequence bindings.
- What you can do after
- Apply it in `let` or function parameters to unpack map inputs, provide absent-key defaults, and retain the original map.
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Get Programming with JavaScript Next: New features of ECMAScript 2015, 2016, and beyond
A JavaScript assignment form that extracts properties from an object into distinct variables, optionally renaming the bindings.
- How it is used
- Replaces repeated property and index lookups when unpacking data structures or passing their values into functions.
- How deep it goes
- Works through property names, array positions, renaming, nesting, parameter defaults, and destructurable types; defers the iterable protocol.
- Examples
- Uses coordinates, product data, swapped variables, visualization inputs, and optional car settings to demonstrate patterns.
- What you can do after
- Practice/perform nested extraction, binding renames, variable swaps, and parameter unpacking with optional defaults.
React Quickly, Second Edition
Object destructuring is a JavaScript syntax feature that extracts properties from an object into named bindings.
- How it is used
- Simplifies access to props when defining functional React components.
- How deep it goes
- Defines object extraction, compares parameter-list and body forms, and extends to rest without exploring deeper language mechanics.
- Examples
- Uses an object assignment, a menu link component, and a class-to-function image gallery conversion.
- What you can do after
- Apply it via React functional components to name props directly and collect remaining props for pass-through.
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Learn Rust in a Month of Lunches
Destructuring is Rust syntax that binds the components of a composite value to separate variables through a matching pattern.
- How it is used
- Uses matching patterns to extract selected values from tuples, structs, enums, and function arguments.
- How deep it goes
- Explains tuple matching, ignored components, ownership moves, struct renaming, omitted fields, and parameter patterns.
- Examples
- Demonstrates tuple extraction, underscore omission, renamed Person fields, omitted City fields, and destructured function parameters.
- What you can do after
- Apply it in Rust to bind composite values, ignore unwanted parts, rename fields, and destructure function inputs.
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Refactoring to Rust
Destructuring is the extraction of component values from structured values such as enum variants through pattern matching.
- How it is used
- Extracts data stored in enum variants while handling each variant with a match expression.
- How deep it goes
- Defines payload binding and variant checking through a worked FizzBuzz example, without extending beyond enum matching.
- Examples
- Uses FizzBuzzValue::NotDivisible(i32) and binds its number as num in a match arm.
- What you can do after
- Apply it via Rust match arms to retrieve enum data safely after confirming the variant.
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Idiomatic Rust
Destructuring is the decomposition of a compound value into bindings for selected or constituent parts through a pattern.
- How it is used
- Uses patterns in `match` expressions to access selected or constituent parts of compound values.
- How deep it goes
- Demonstrates partial and complete tuple, struct, and enum destructuring through match patterns.
- Examples
- Shows tuple element selection, struct field matching, and enum variant bindings.
- What you can do after
- Apply pattern matching to bind values from tuples, structs, and enum variants.
Related concepts
- tupleuses · A tuple is a finite, ordered collection of elements treated as a single composite value or record.
- objectuses · A computational object is a runtime entity or structured value representing data, state, or a resource, with properties or operations defined by its programming model.
- arrayuses · An array is an indexed, ordered collection of elements arranged in one or more dimensions, with elements accessed by position.
- enumuses · An enum is a type or language construct whose values are selected from a finite set of named alternatives, which may carry associated data.
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