This is the fourth day of my participation in Gwen Challenge
56. What is the output?
const set = new Set([1.1.2.3.4]);
console.log(set);
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D) Print out 1, 2, 3, 4.
57. What is the output?
// counter.js
let counter = 10;
export default counter;
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import myCounter from "./counter";
myCounter += 1;
console.log(myCounter);
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A: C, the imported module is read-only and cannot be modified.
58. What is the output?
const name = "Lydia";
age = 21;
console.log(delete name);
console.log(delete age);
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A: A, just remember that attributes can be deleted, and defined variables cannot be deleted. Age is equivalent to adding attributes to global objects, and name is A defined variable.
59. What is the output?
const numbers = [1.2.3.4.5];
const [y] = numbers;
console.log(y);
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Y = 1; y = 1; y = 1;
60. What is the output?
const user = { name: "Lydia".age: 21 };
const admin = { admin: true. user };console.log(admin);
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B) deconstruct the object by extending the operator.
61. What is the output?
const person = { name: "Lydia" };
Object.defineProperty(person, "age", { value: 21 });
console.log(person);
console.log(Object.keys(person));
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A) defineProperty B) defineProperty D) defineProperty
62. What is the output?
const settings = {
username: "lydiahallie".level: 19.health: 90
};
const data = JSON.stringify(settings, ["level"."health"]);
console.log(data);
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Json.stringify is A string that can be converted to A string.
63. What is the output?
let num = 10;
const increaseNumber = () = > num++;
const increasePassedNumber = number= > number++;
const num1 = increaseNumber();
const num2 = increasePassedNumber(num1);
console.log(num1);
console.log(num2);
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A: x++ is called in the same order as x++.
64. What is the output?
const value = { number: 10 };
const multiply = (x = { ... value }) = > {
console.log(x.number *= 2);
};
multiply();
multiply();
multiply(value);
multiply(value);
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C) If a parameter is passed by default, a new object is created each time. If a parameter is passed by default, a new object is created each time.
65. What is the output?
[1.2.3.4].reduce((x, y) = > console.log(x, y));
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The first parameter of reduce is the cumulator value, and the second parameter is the current element value. If the cumulator value is not specified, then the cumulator value is the value of the first element, that is, 1, and y is 2. The accumulator is undefined because there is no addition or subtraction operation.
Title source
Github.com/lydiahallie…