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Array Superpowers: JavaScript: Uncharted

Courses JavaScriptArray Superpowers

Array Superpowers

Transform, select, combine, search, check, sort, and chain arrays with methods that reveal each job’s shape.

JavaScript
Unit 10 of 20
20 lessons
176 min
420 XP

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Lessons

20 total

1Three MachinesMatch transform, keep, and combine jobs to the array method designed for each one.InteractiveConcept6 min20 XPOpen
2map TransformsUse map to calculate a tax-inclusive value for every price without changing the input.CodeConcept8 min20 XPOpen
3map Over ObjectsUse map to pull one property from every object in a roster.CodeConcept8 min20 XPOpen
4filter KeepsUse filter to return only products that are currently in stock.CodeConcept8 min20 XPOpen
5find the FirstUse find and findIndex to retrieve the first matching item and its position.CodeConcept8 min20 XPOpen
6Any and AllUse some and every to answer two collection-wide yes-or-no questions.CodeConcept8 min20 XPOpen
7Pick the ToolSelect map, filter, find, some, and every from the result each question needs.InteractiveConcept8 min20 XPOpen
8reduce, the Honest WayBuild a sum by tracing reduce as an accumulator updated once per item.CodeConcept8 min20 XPOpen
9reduce to a TallyUse reduce to accumulate repeated votes into an object of counts.CodeConcept9 min20 XPOpen
10sort With CareSort a copied score list numerically while avoiding the default string-order trap.CodeConcept9 min20 XPOpen
11Chains That ReadChain filter, map, and join in the order described by a reporting task.CodeConcept9 min20 XPOpen
12Order the ChainArrange array-processing steps so each intermediate result fits the next step.InteractiveConcept7 min20 XPOpen
13forEach vs mapFix a silent transformation bug by returning the array created by map.CodeConcept8 min20 XPOpen
14Plan to MovesMap a fixed array of route words into callable courier moves, then run them.Code worldConcept10 min20 XPOpen
15Playlist StatsReduce a playlist into its count, total duration, and longest track.CodePractice11 min20 XPOpen
16Expense ReportFilter expenses by month, reduce their total, and format a currency label.CodePractice11 min20 XPOpen
17Predict the ChainPredict a filter-map-slice chain by tracing each intermediate array.InteractiveConcept8 min20 XPOpen
18Leaderboard Top ThreeSort a copy, take three entries, and map them into ranked leaderboard labels.CodePractice11 min20 XPOpen
19Why New ArraysExplain how map returning a new array helps prevent shared-state bugs.InteractiveConcept9 min20 XPOpen
20Superpowers Mastery CheckCombine transformation, selection, accumulation, finding, checks, sorting, and chaining in one order report.CodeMastery check12 min40 XPOpen

Strings in Depth Scope and Closures