Count Completed Tasks with JavaScript
Topic: bindings, values, and coercion
Write a small function that counts completed tasks in an array of objects.
All course tracks
Programming languages · 30 lessons · up to 10 minutes each
JavaScript
A progressive JavaScript sequence with one free-preview array exercise; the other 29 listings are planned.
1 lesson available
Beginner
Lessons 1–10
01 02 JavaScript: Name the parts of expressions, conditions, and iteration
Topic: expressions, conditions, and iteration
Label the main pieces in expressions, conditions, and iteration in the context of JavaScript language behavior in browsers and runtimes; save a short example or check that demonstrates the result.
Beginner5 minComing Soon03 JavaScript: Trace an example of functions, scope, and closures
Topic: functions, scope, and closures
Follow one input through functions, scope, and closures in the context of JavaScript language behavior in browsers and runtimes; save a short example or check that demonstrates the result.
Beginner6 minComing Soon04 JavaScript: Compare choices for objects, prototypes, and classes
Topic: objects, prototypes, and classes
Write down one practical difference between objects, prototypes, and classes in the context of JavaScript language behavior in browsers and runtimes; save a short example or check that demonstrates the result.
Beginner7 minComing Soon05 JavaScript: Find the boundary in arrays, maps, sets, and callbacks
Topic: arrays, maps, sets, and callbacks
Mark where arrays, maps, sets, and callbacks in the context of JavaScript language behavior in browsers and runtimes; save a short example or check that demonstrates the result.
Beginner8 minComing Soon06 JavaScript: Inspect an example of modules and dependency boundaries
Topic: modules and dependency boundaries
Annotate a minimal example of modules and dependency boundaries in the context of JavaScript language behavior in browsers and runtimes; save a short example or check that demonstrates the result.
Beginner9 minComing Soon07 JavaScript: Connect promises, async functions, and errors to a neighboring concept
Topic: promises, async functions, and errors
Show how promises, async functions, and errors in the context of JavaScript language behavior in browsers and runtimes; save a short example or check that demonstrates the result.
Beginner10 minComing Soon08 JavaScript: Spot a failure mode in DOM events, forms, and fetch
Topic: DOM events, forms, and fetch
Describe one likely failure for DOM events, forms, and fetch in the context of JavaScript language behavior in browsers and runtimes; save a short example or check that demonstrates the result.
Beginner3 minComing Soon09 JavaScript: Read an official example of testing, debugging, and browser tools
Topic: testing, debugging, and browser tools
Summarize an official example of testing, debugging, and browser tools in the context of JavaScript language behavior in browsers and runtimes; save a short example or check that demonstrates the result.
Beginner5 minComing Soon10 JavaScript: Choose a use case for performance, memory, and runtime behavior
Topic: performance, memory, and runtime behavior
Match one small use case to performance, memory, and runtime behavior in the context of JavaScript language behavior in browsers and runtimes; save a short example or check that demonstrates the result.
Beginner6 minComing Soon
Intermediate
Lessons 11–20
11 JavaScript: Build an example with bindings, values, and coercion
Topic: bindings, values, and coercion
Create a small working example that uses bindings, values, and coercion in the context of JavaScript language behavior in browsers and runtimes; save a short example or check that demonstrates the result.
Intermediate4 minComing Soon12 JavaScript: Compose expressions, conditions, and iteration with another component
Topic: expressions, conditions, and iteration
Combine expressions, conditions, and iteration in the context of JavaScript language behavior in browsers and runtimes; save a short example or check that demonstrates the result.
Intermediate5 minComing Soon13 JavaScript: Configure functions, scope, and closures for a small case
Topic: functions, scope, and closures
Set up functions, scope, and closures in the context of JavaScript language behavior in browsers and runtimes; save a short example or check that demonstrates the result.
Intermediate6 minComing Soon14 JavaScript: Validate inputs around objects, prototypes, and classes
Topic: objects, prototypes, and classes
Add a check around objects, prototypes, and classes in the context of JavaScript language behavior in browsers and runtimes; save a short example or check that demonstrates the result.
Intermediate7 minComing Soon15 JavaScript: Use arrays, maps, sets, and callbacks in a short workflow
Topic: arrays, maps, sets, and callbacks
Add arrays, maps, sets, and callbacks in the context of JavaScript language behavior in browsers and runtimes; save a short example or check that demonstrates the result.
Intermediate8 minComing Soon16 JavaScript: Refactor modules and dependency boundaries into a reusable unit
Topic: modules and dependency boundaries
Extract modules and dependency boundaries in the context of JavaScript language behavior in browsers and runtimes; save a short example or check that demonstrates the result.
Intermediate9 minComing Soon17 JavaScript: Exercise promises, async functions, and errors with sample data
Topic: promises, async functions, and errors
Run sample data through promises, async functions, and errors in the context of JavaScript language behavior in browsers and runtimes; save a short example or check that demonstrates the result.
Intermediate10 minComing Soon18 JavaScript: Observe DOM events, forms, and fetch outputs
Topic: DOM events, forms, and fetch
Capture the result of DOM events, forms, and fetch in the context of JavaScript language behavior in browsers and runtimes; save a short example or check that demonstrates the result.
Intermediate3 minComing Soon19 JavaScript: Recover from a testing, debugging, and browser tools failure
Topic: testing, debugging, and browser tools
Handle one expected failure from testing, debugging, and browser tools in the context of JavaScript language behavior in browsers and runtimes; save a short example or check that demonstrates the result.
Intermediate5 minComing Soon20 JavaScript: Document performance, memory, and runtime behavior behavior
Topic: performance, memory, and runtime behavior
Write a short usage note for performance, memory, and runtime behavior in the context of JavaScript language behavior in browsers and runtimes; save a short example or check that demonstrates the result.
Intermediate6 minComing Soon
Advanced
Lessons 21–30
21 JavaScript: Test a boundary around bindings, values, and coercion
Topic: bindings, values, and coercion
Add an edge-case test for bindings, values, and coercion in the context of JavaScript language behavior in browsers and runtimes; save a short example or check that demonstrates the result.
Advanced4 minComing Soon22 JavaScript: Harden expressions, conditions, and iteration
Topic: expressions, conditions, and iteration
Add the relevant access, safety, or validation control to expressions, conditions, and iteration in the context of JavaScript language behavior in browsers and runtimes; save a short example or check that demonstrates the result.
Advanced5 minComing Soon23 JavaScript: Measure functions, scope, and closures
Topic: functions, scope, and closures
Record a small baseline for functions, scope, and closures in the context of JavaScript language behavior in browsers and runtimes; save a short example or check that demonstrates the result.
Advanced6 minComing Soon24 JavaScript: Reduce cost in objects, prototypes, and classes
Topic: objects, prototypes, and classes
Change one measurable cost in objects, prototypes, and classes in the context of JavaScript language behavior in browsers and runtimes; save a short example or check that demonstrates the result.
Advanced7 minComing Soon25 JavaScript: Diagnose a arrays, maps, sets, and callbacks failure
Topic: arrays, maps, sets, and callbacks
Use an observable signal to explain a failure in arrays, maps, sets, and callbacks in the context of JavaScript language behavior in browsers and runtimes; save a short example or check that demonstrates the result.
Advanced8 minComing Soon26 JavaScript: Make modules and dependency boundaries repeatable
Topic: modules and dependency boundaries
Show that rerunning modules and dependency boundaries in the context of JavaScript language behavior in browsers and runtimes; save a short example or check that demonstrates the result.
Advanced9 minComing Soon27 JavaScript: Review trade-offs in promises, async functions, and errors
Topic: promises, async functions, and errors
Compare two documented approaches to promises, async functions, and errors in the context of JavaScript language behavior in browsers and runtimes; save a short example or check that demonstrates the result.
Advanced10 minComing Soon28 JavaScript: Improve DOM events, forms, and fetch maintainability
Topic: DOM events, forms, and fetch
Refine DOM events, forms, and fetch in the context of JavaScript language behavior in browsers and runtimes; save a short example or check that demonstrates the result.
Advanced3 minComing Soon29 JavaScript: Verify testing, debugging, and browser tools end to end
Topic: testing, debugging, and browser tools
Check that a complete small flow using testing, debugging, and browser tools in the context of JavaScript language behavior in browsers and runtimes; save a short example or check that demonstrates the result.
Advanced5 minComing Soon30 JavaScript: Audit performance, memory, and runtime behavior against its source docs
Topic: performance, memory, and runtime behavior
Check the implementation of performance, memory, and runtime behavior in the context of JavaScript language behavior in browsers and runtimes; save a short example or check that demonstrates the result.
Advanced6 minComing Soon
Reference documentation
References support the selected track topics while its lesson content is built and reviewed progressively.
One JavaScript preview lesson is ready. The other 29 listings are planned and unavailable.