JavaScript Mastery in 14 Days

Master JavaScript fundamentals and advanced patterns through hands-on practice. Covers closures, promises, async patterns, and functional programming. 2 problems per day for comprehensive learning.

14 days

Beginner

32 milestones

Your Progress

0 of 32 milestones completed

You're 0% closer to JavaScript Interview Mastery

Recommended Model

Days 1-8FREE

Free core foundation with progressive interview patterns

Day 9STREAK UNLOCK

Streak unlock or 3-problem preview/day to maintain momentum

Days 10-14PRO

Pro-only advanced track: orchestration, edge cases, and capstone

Learning Focus

Build closure + async fluency with interview-grade JavaScript patterns

Progressively ramp from fundamentals to capstone-level implementation challenges

Convert daily practice into repeatable performance under timed interview pressure

Retention Mechanics

Daily streak checkpoints with unlock momentum from Day 9

Skill-tag based revision loops to revisit weak spots

Capstone day with advanced variants to consolidate long-term recall

Daily Plan

32 problems0 concepts0 system design32 total

Day 1: Timers + Rate Limiting I

FOUNDATIONFREE

0 of 2 completed

Core UI primitives: debounce + throttle. Nail signatures + edge cases.

TimersClosures

Debounce Function

Problem

Throttle Function

Problem

Day 2: Timers + Rate Limiting II

INTERMEDIATEFREE

0 of 2 completed

Enhanced variants = where most candidates fail.

Trailing/LeadingCancel/Flush

Advanced Debounce Function

Problem

Enhanced Throttle Function

Problem

Day 3: Timers + Rate Limiting III

ADVANCEDFREE

0 of 2 completed

Hard throttle variant to prove mastery.

Hard Edge CasesCorrectness

Advanced Throttle Function

Problem

Counter Function with Closure

Problem

Day 4: Eventing I

FOUNDATIONFREE

0 of 2 completed

Classic interview question. Contracts matter.

PubSubData Structures

Event Emitter

Problem

Enhanced Event Emitter

Problem

Day 5: Eventing II

ADVANCEDFREE

0 of 2 completed

Advanced emitter = unsubscribe correctness + ordering + memory hygiene.

Edge CasesPerformance

Advanced Event Emitter

Problem

Once Function

Problem

Day 6: Promises I (Combinators)

INTERMEDIATEFREE

0 of 2 completed

Promise.all + race = core async semantics.

PromisesDeterminism

Promise.all (Polyfill)

Problem

Promise.race

Problem

Day 7: Promises II (Variants)

INTERMEDIATEFREE

0 of 2 completed

These separate “knows promises” vs “really knows promises.”

AllSettledAny

Promise.any

Problem

Promise.allSettled

Problem

Day 8: Promises III (Control Flow)

ADVANCEDFREE

0 of 3 completed

Real-world async: limit concurrency, retry with backoff, enforce timeouts.

ConcurrencyRetriesTimeouts

Day 9: Promise Foundations

ADVANCEDPRO

0 of 2 completed

Constructor polyfill + resolve/reject polyfill = serious signal.

Spec-Level Behavior

Promise Constructor Polyfill

Problem

Promise.resolve and Promise.reject Polyfill

Problem

Day 10: Cloning I

FOUNDATIONFREE

0 of 2 completed

Deep clone basics + circular refs.

ObjectsReferences

Deep Clone

Problem

Deep Clone with Circular References

Problem

Day 11: Cloning II

ADVANCEDFREE

0 of 2 completed

Complete clone variant = interview finisher.

Edge TypesCorrectness

Complete Deep Clone

Problem

LocalStorage with Expiration

Problem

Day 12: Serialization I

FOUNDATIONFREE

0 of 2 completed

JSON stringify/parse teaches contracts and edge cases.

SerializationJSON

JSON.stringify - Simple

Problem

JSON.parse - Simple

Problem

Day 13: Serialization II

ADVANCEDFREE

0 of 2 completed

Complex variants = where correctness matters most.

CyclesUnsupported Types

JSON.stringify - Complex

Problem

JSON.parse - Complex

Problem

Day 14: DOM + Polyfills Capstone

INTERVIEWFREE

0 of 5 completed

Great capstone set: DOM tree modeling + traversal + array polyfills.

DOMTraversalPolyfills

JS Track FinisherProfile Highlight

Get DOM Tree Height

Problem

Traverse DOM Level by Level

Problem

Array.prototype.filter (Polyfill)

Problem

Array.prototype.map (Polyfill)

Problem

Array.prototype.reduce (Polyfill)

Problem

Start First Milestone

Back to explore

JavaScript Mastery in 14 Days

Master JavaScript fundamentals and advanced patterns through hands-on practice. Covers closures, promises, async patterns, and functional programming. 2 problems per day for comprehensive learning.

14 days

Beginner

32 milestones

Your Progress

0 of 32 milestones completed

You're 0% closer to JavaScript Interview Mastery

Recommended Model

Days 1-8FREE

Free core foundation with progressive interview patterns

Day 9STREAK UNLOCK

Streak unlock or 3-problem preview/day to maintain momentum

Days 10-14PRO

Pro-only advanced track: orchestration, edge cases, and capstone

Learning Focus

Build closure + async fluency with interview-grade JavaScript patterns

Progressively ramp from fundamentals to capstone-level implementation challenges

Convert daily practice into repeatable performance under timed interview pressure

Retention Mechanics

Daily streak checkpoints with unlock momentum from Day 9

Skill-tag based revision loops to revisit weak spots

Capstone day with advanced variants to consolidate long-term recall

Daily Plan

32 problems0 concepts0 system design32 total

Day 1: Timers + Rate Limiting I

FOUNDATIONFREE

0 of 2 completed

Core UI primitives: debounce + throttle. Nail signatures + edge cases.

TimersClosures

Debounce Function

Problem

Throttle Function

Problem

Day 2: Timers + Rate Limiting II

INTERMEDIATEFREE

0 of 2 completed

Enhanced variants = where most candidates fail.

Trailing/LeadingCancel/Flush

Advanced Debounce Function

Problem

Enhanced Throttle Function

Problem

Day 3: Timers + Rate Limiting III

ADVANCEDFREE

0 of 2 completed

Hard throttle variant to prove mastery.

Hard Edge CasesCorrectness

Advanced Throttle Function

Problem

Counter Function with Closure

Problem

Day 4: Eventing I

FOUNDATIONFREE

0 of 2 completed

Classic interview question. Contracts matter.

PubSubData Structures

Event Emitter

Problem

Enhanced Event Emitter

Problem

Day 5: Eventing II

ADVANCEDFREE

0 of 2 completed

Advanced emitter = unsubscribe correctness + ordering + memory hygiene.

Edge CasesPerformance

Advanced Event Emitter

Problem

Once Function

Problem

Day 6: Promises I (Combinators)

INTERMEDIATEFREE

0 of 2 completed

Promise.all + race = core async semantics.

PromisesDeterminism

Promise.all (Polyfill)

Problem

Promise.race

Problem

Day 7: Promises II (Variants)

INTERMEDIATEFREE

0 of 2 completed

These separate “knows promises” vs “really knows promises.”

AllSettledAny

Promise.any

Problem

Promise.allSettled

Problem

Day 8: Promises III (Control Flow)

ADVANCEDFREE

0 of 3 completed

Real-world async: limit concurrency, retry with backoff, enforce timeouts.

ConcurrencyRetriesTimeouts

Promise Limit - K Parallel Tasks

Problem

Promise Retry with Backoff

Problem

Promise Timeout

Problem

Day 9: Promise Foundations

ADVANCEDPRO

0 of 2 completed

Constructor polyfill + resolve/reject polyfill = serious signal.

Spec-Level Behavior

Promise Constructor Polyfill

Problem

Promise.resolve and Promise.reject Polyfill

Problem

Day 10: Cloning I

FOUNDATIONFREE

0 of 2 completed

Deep clone basics + circular refs.

ObjectsReferences

Deep Clone

Problem

Deep Clone with Circular References

Problem

Day 11: Cloning II

ADVANCEDFREE

0 of 2 completed

Complete clone variant = interview finisher.

Edge TypesCorrectness

Complete Deep Clone

Problem

LocalStorage with Expiration

Problem

Day 12: Serialization I

FOUNDATIONFREE

0 of 2 completed

JSON stringify/parse teaches contracts and edge cases.

SerializationJSON

JSON.stringify - Simple

Problem

JSON.parse - Simple

Problem

Day 13: Serialization II

ADVANCEDFREE

0 of 2 completed

Complex variants = where correctness matters most.

CyclesUnsupported Types

JSON.stringify - Complex

Problem

JSON.parse - Complex

Problem

Day 14: DOM + Polyfills Capstone

INTERVIEWFREE

0 of 5 completed

Great capstone set: DOM tree modeling + traversal + array polyfills.

DOMTraversalPolyfills

JS Track FinisherProfile Highlight

Get DOM Tree Height

Problem

Traverse DOM Level by Level

Problem

Array.prototype.filter (Polyfill)

Problem

Array.prototype.map (Polyfill)

Problem

Array.prototype.reduce (Polyfill)

Problem

Start First Milestone