devlearn-javascript — reference

MDN quick links

<scriptsrc="app.js" defer></script>

Attribute	Effect
defer	Run after HTML parsed, order preserved
type="module"	ES modules, strict mode, defer implied

/** @type {{ id: string, text: string, done: boolean }[]} */lettodos=[];

constid=crypto.randomUUID?.()??String(Date.now());

Explain: stable id for delete/toggle.

functiondeleteTodo(id){todos=todos.filter((t)=>t.id!==id);render();}

Teach filter as "keep todos whose id doesn't match."

asyncfunctionloadTodos(){constresponse=awaitfetch('/api/todos');todos=awaitresponse.json();render();}

Order: fetch returns Promise → await pauses function until data → json parses body.

Tool	Use
console.log	See values
breakpoint	Pause on line in Sources tab
Network tab	See fetch requests (apis skill)