ES6 perguntas e respostas de entrevista
Pergunta 16. Explain the concept of the 'Symbol' data type in ES6.
Symbols are a new primitive data type in ES6, used to create unique identifiers.
Example:
const mySymbol = Symbol('description');
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Pergunta 17. What is the purpose of the 'Set' data structure in ES6?
A Set is a collection of values with no duplicate entries. It is iterable and can store various types of values.
Example:
const uniqueNumbers = new Set([1, 2, 3, 2, 1]);
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Pergunta 18. Explain the 'WeakMap' and 'WeakSet' data structures in ES6.
WeakMap and WeakSet are similar to Map and Set, respectively, but they allow for garbage collection of keys and values that are not used elsewhere.
Example:
let weakMap = new WeakMap(); let obj = {}; weakMap.set(obj, 'some value');
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Pergunta 19. What is the 'Proxy' object in ES6?
The Proxy object is used to define custom behavior for fundamental operations (e.g., property lookup, assignment, enumeration, etc.).
Example:
const handler = { get: function(target, prop) { return prop in target ? target[prop] : 'Not found'; } }; const proxy = new Proxy({}, handler);
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Pergunta 20. Explain the concept of the 'Reflect' object in ES6.
The Reflect object provides methods for interceptable JavaScript operations. It is used for method invocation, property manipulation, etc.
Example:
Reflect.has(obj, 'property');
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