All
An all operation returns a Boolean indicating whether every item in a collection satisfies a condition, or is truthy when no condition is specified.
Secrets of the JavaScript Ninja, Second Edition
An Array method that returns true if every element passes a callback test.
- How it is used
- Tests whether every item in an array satisfies a condition.
- How deep it goes
- Shows callback-based condition checks with examples that produce true and false results.
- Examples
- Tests whether ninja objects all have names or weapons.
- What you can do after
- Apply Array.prototype.every to test whether each array item meets a condition.
Read how Secrets of the JavaScript Ninja, Second Edition explains all →
Data-Oriented Programming: Reduce software complexity
_.every is a Lodash function that returns true when a predicate returns true for every element of a collection.
- How it is used
- Groups related search assertions into compact unit tests for queries expected to return books or no books.
- How deep it goes
- Defines the collection-and-predicate contract and demonstrates grouped tests, but does not descend into Lodash implementation internals.
- Examples
- Uses grouped positive and negative search queries against captured catalog data, including Habit, habit, abit, and bit.
- What you can do after
- Apply it via Lodash to verify that every input produces an expected result within one predicate-driven test.
Read how Data-Oriented Programming: Reduce software complexity explains all →
Learn Rust in a Month of Lunches
- How it is used
- Checks whether every item in an iterator satisfies a predicate.
- How deep it goes
- Explains predicate use, reference handling, and the FnMut signature without descending into iterator internals.
- Examples
- Uses character ranges to test alphabetic characters and ordering against a Korean character.
- What you can do after
- Apply it via Rust iterator methods to test collection-wide conditions with closures.
Clojure: The Essential Reference
every? is a Clojure function that tests whether a predicate returns truthy for every element of a collection.
- How it is used
- Answers whether all elements of a collection satisfy a predicate.
- How deep it goes
- Defines inputs, truthiness, outputs, accepted collections, exceptions, logical relatives, and empty-collection behavior.
- Examples
- Uses positive numbers, nested sequences, bingo cards, empty collections, and large ranges.
- What you can do after
- Apply every? to validate that all values in a collection satisfy a Clojure predicate.
Related concepts
- anycontrasts with · An any or some operation returns a Boolean indicating whether at least one element in a collection satisfies a predicate or, when none is supplied, is truthy.
- Monoproduces · Mono is a Project Reactor publisher type representing an asynchronous computation that emits zero or one item.
- Fluxuses · Flux is a Project Reactor publisher type representing an asynchronous sequence that emits zero or more ordered values.
- not-every?equivalent to · not-every? is a Clojure function that returns the logical negation of every? for a predicate and collection.
- logical AND operatorequivalent to · A logical AND operator is a Boolean conjunction that produces true exactly when all operands have true truth values.
- higher-order functionkind of · A higher-order function is a function that accepts functions as arguments, returns functions as results, or both.
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