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Remember with Variables: JavaScript: Uncharted

Courses JavaScriptRemember with Variables

Remember with Variables

Name fixed facts, update changing values, choose readable identifiers, and trace state one statement at a time.

JavaScript
Unit 2 of 20
20 lessons
163 min
420 XP

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Lessons

20 total

1Boxes with LabelsRecognize a variable as a name that remembers one current value.InteractiveConcept6 min20 XPOpen
2Your First letDeclare a variable with let and print its stored value by name.CodeConcept7 min20 XPOpen
3const Means PromiseDeclare a fixed fact with const and use it without reassigning its name.CodeConcept7 min20 XPOpen
4Counters CountUpdate a let variable when a new event changes its stored count.CodeConcept8 min20 XPOpen
5The Cup SwapSwap two variable values safely by holding one value in a temporary variable.CodeConcept9 min20 XPOpen
6Names That Mean ThingsReplace cryptic variable names with names that explain the values they hold.CodeConcept8 min20 XPOpen
7Trace the ValueTrace one variable through three statements to determine its final value.InteractiveConcept7 min20 XPOpen
8Running a BudgetBuild later budget variables from values already stored under clear names.CodeConcept9 min20 XPOpen
9Order of UpdatesArrange variable updates so each statement receives the intended current value.InteractiveConcept8 min20 XPOpen
10Before It's SetMove a let declaration before the first instruction that uses its name.CodeConcept8 min20 XPOpen
11Shortcut OperatorsUse +=, -=, and ++ to express three concise updates to one variable.CodeConcept8 min20 XPOpen
12let vs const CallsChoose const for profile fields that this program never reassigns.InteractiveConcept7 min20 XPOpen
13Streak KeeperUpdate one streak variable after each completed learning event.CodePractice8 min20 XPOpen
14Water Bottle MathTrack refills and sips by adding to and subtracting from one stored amount.CodePractice8 min20 XPOpen
15Two Variables TangoPredict how a derived variable behaves after its source variable changes.CodeConcept8 min20 XPOpen
16Predict After UpdatesTrace three updates and identify the value printed at the end.InteractiveConcept7 min20 XPOpen
17ScorekeeperTrack two players independently across three rounds of score updates.CodePractice10 min20 XPOpen
18Why const FirstExplain how defaulting to const makes a program easier to read and reason about.InteractiveConcept8 min20 XPOpen
19Day Counter ChainBuild a manual countdown by printing and updating one day counter in sequence.CodePractice10 min20 XPOpen
20Variables Mastery CheckBuild a clear shift summary with fixed facts, mutable state, and derived values.CodeMastery check12 min40 XPOpen

Hello, JavaScript Numbers and Text