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JavaScript foundations for TypeScript

A migration-focused route through JavaScript values, object behavior, asynchronous control flow, and the runtime boundaries that static types cannot verify.

24 topics 4 checkpoints about 22 h beginner → intermediate
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0 of 24 topics · milestone 1 of 4 Continue: JavaScript fundamentals

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JavaScript foundations for TypeScript: 24 topics, 4 checkpoints. JavaScript fundamentals Data types Functions Array methods Object static methods Destructuring assignment Arrow functions Closures this binding call, apply and bind Objects and prototypes Classes The event loop Modules Error handling JSON

Milestone 1 · Dynamic values and transformations

0 of 6 topics · about 106 min
now JavaScript fundamentals 18 min 2 Data types 18 min 3 Functions 18 min 4 Array methods 14 min 5 Object static methods 17 min 6 Destructuring assignment 21 min
Checkpoint 1 unlocks M2

Milestone 2 · Scope, receivers, and objects

0 of 6 topics · about 99 min
1 Arrow functions 14 min 2 Closures 21 min 3 this binding 17 min 4 call, apply and bind 15 min 5 Objects and prototypes 17 min 6 Classes 15 min
Checkpoint 2 unlocks M3

Milestone 3 · Asynchronous contracts

0 of 6 topics · about 62 min
1 The event loop 12 min
soon Promises 10 min
soon Promise methods 10 min
soon Async await 10 min
soon Async iterators 10 min
soon Streams 10 min
Checkpoint 3 unlocks M4

Milestone 4 · Migration boundaries and safeguards

0 of 6 topics · about 82 min
1 Modules 18 min 2 Error handling 17 min 3 JSON 17 min
soon Form validation 10 min
soon Vitest 10 min
soon Alpinejs 10 min
Checkpoint 4 done

Why this order: Start with JavaScript values and transformations because TypeScript describes those runtime operations rather than replacing them. Then make scope, receivers, prototypes, and classes explicit before modeling object contracts. Learn promises and streams next so asynchronous return and failure paths are clear. Finish with modules, runtime validation, tests, and a small Alpine.js boundary, where a staged migration needs its strongest safeguards.