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← Introduction to JavaScript
○What is JavaScript?○Your First JavaScript Code○Data Types○Type Checking
○Declaring Variables○let and const in Practice○Operators○Type Conversion
○Conditionals○Switch Statement○For Loops○While Loop○Break and Continue
○Defining Functions○Arrow Functions○Scope○Closures○Project - Calculator○Function Expressions
○Arrays○Array Mutation Methods○Array Search and Slice○Array Iteration Methods○Multidimensional Arrays○Destructuring○Array Reverse and Sort○Array Fill○Array Find and Includes○Array Flat and FlatMap●Array Reduce, Some, and Every
○Objects○Object Methods and Destructuring○JSON○Math and Date○Date Basics
○02 Template Literals○String Methods○Regular Expressions
○Higher-Order Functions○Callbacks○map, filter, and reduce○Recursion○Project - Data Transform Pipeline
○OOP Introduction○Classes○Inheritance○Encapsulation
○Asynchronous JavaScript○Promises and Async Await○Async API Simulation

Array Reduce, Some, and Every

Some array methods return one combined answer instead of a new array. This lesson uses reduce(), some(), and every() together to show three different kinds of summary.

Example

javascript
const total = [5, 10, 15].reduce((sum, value) => sum + value, 0);
const hasAdult = [12, 17, 21].some((age) => age >= 18);
const allPositive = [1, 2, 3].every((n) => n > 0);

Your Task

  1. Create total, hasAdult, and allPositive using reduce(), some(), and every() on the example arrays.
  2. Display 30 | true | true in #output.
Hint 1
1 / 2
HINT 1

Use reduce() to total the numbers into one value.

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