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JavaScript: Test whether a given array of integers contains 30 or 40 twice

JavaScript Basic: Exercise-79 with Solution

Write a JavaScript program to test whether a given array of integers contains 30 or 40 twice. The array length should be 0, 1, or 2.

Pictorial Presentation:

JavaScript: Test whether a given array of integers contains 30 or 40 twice.

Sample Solution:

HTML Code:

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width">
  <title>JavaScript program to test whether a given array of integers contains 30 or 40 twice. The array length should be 0, 1, or 2.</title>
</head>
<body>

</body>
</html>

JavaScript Code:

function twice3040(arra1) {
    let a = arra1[0],
        b = arra1[1];
    return (a === 30 && b === 30) || (a === 40 && b === 40);
}

console.log(twice3040([30, 30]));
console.log(twice3040([40, 40]));
console.log(twice3040([20, 20]));
console.log(twice3040([30]));

Sample Output:

true
true
false
true

Flowchart:

Flowchart: JavaScript - Test whether a given array of integers contains 30 or 40 twice

ES6 Version:

function twice3040(arra1) {
    let a = arra1[0];
    let b = arra1[1];
    return (a === 30 && b === 30) || (a === 40 && b === 40);
}

console.log(twice3040([30, 30]));
console.log(twice3040([40, 40]));
console.log(twice3040([20, 20]));
console.log(twice3040([30]));

Live Demo:

See the Pen JavaScript - Test whether an array of integers of length 2 does not contain 1 or a 3-basic-ex-78 by w3resource (@w3resource) on CodePen.


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Previous: Write a JavaScript program to test whether an array of integers of length 2 does not contain 1 or a 3.
Next: Write a JavaScript program to swap the first and last elements of a given array of integers. The array length should be at least 1.

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JavaScript: Tips of the Day

Parameter's value

function getItems(fruitList, ...args, favoriteFruit) {
  return [...fruitList, ...args, favoriteFruit]
}

getItems(["banana", "apple"], "pear", "orange")

...args is a rest parameter. The rest parameter's value is an array containing all remaining arguments, and can only be the last parameter! In this example, the rest parameter was the second parameter. This is not possible, and will throw a syntax error.

function getItems(fruitList, favoriteFruit, ...args) {
  return [...fruitList, ...args, favoriteFruit];
}


getItems(['banana', 'apple'], 'pear', 'orange');
The above example works. This returns the array [ 'banana', 'apple', 'orange', 'pear' ].

Ref: https://bit.ly/3jFRBje