For...of
The JavaScript for...of statement iterates over successive values produced by an iterable's iterator.
Secrets of the JavaScript Ninja, Second Edition
A JavaScript loop that iterates over iterable values using the iterator protocol.
- How it is used
- Consumes generator-produced sequences without manual iterator control.
- How deep it goes
- Explains next() results through value and done, then characterizes for...of as shorthand for iterator control.
- Examples
- Uses WeaponGenerator to yield weapons and a warrior generator that delegates to a ninja generator.
- What you can do after
- Apply it to consume values yielded by a generator without writing iterator-control code.
Read how Secrets of the JavaScript Ninja, Second Edition explains for...of →
Get Programming with JavaScript Next: New features of ECMAScript 2015, 2016, and beyond
A JavaScript looping statement that iterates over iterable values by repeatedly obtaining successive items from an iterator.
- How it is used
- Processes iterable values one at a time, including values in arrays, strings, Sets, and Maps.
- How deep it goes
- Defines value iteration, compares it with for...in and forEach, and demonstrates early exit and generator use without detailing iterator internals.
- Examples
- Contrasts object-key and array-value loops, then uses nested loops to create a card deck from suits and faces.
- What you can do after
- Apply it to process iterable values, stop early with break, or yield values from a generator loop.
Related concepts
- iteratoruses · An iterator is an object or abstraction that provides successive values from a sequence or data source through a traversal protocol.
- Mapuses · A map is an associative data structure that stores key-value pairs and supports retrieving values by key.
- iterableuses · An iterable is an object or value that provides or supports a protocol for producing its elements sequentially.
- setuses · A set is a collection of unique elements in which membership is determined by whether an element is present, not by duplicate occurrences.
- loopcontrasts with · A loop is a programming control-flow construct that repeatedly executes a block of instructions according to an iteration rule or continuation condition.
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