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JavaScript: Cast the provided value as an array if it's not one

JavaScript fundamental (ES6 Syntax): Exercise-61 with Solution

Write a JavaScript program to cast the provided value as an array if it's not one.

  • Use Array.prototype.isArray() to determine if val is an array and return it as-is or encapsulated in an array accordingly.

Sample Solution:

JavaScript Code:

//#Source https://bit.ly/2neWfJ2 
const castArray = val => (Array.isArray(val) ? val : [val]);
console.log(castArray('w3r')); 
console.log(castArray([100]));

Sample Output:

["w3r"]
[100]

Pictorial Presentation:

JavaScript Fundamental: Cast the provided value as an array if it's not one

Flowchart:

flowchart: Cast the provided value as an array if it's not one

Live Demo:

See the Pen javascript-basic-exercise-61-1 by w3resource (@w3resource) on CodePen.


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Previous: Write a JavaScript program to create a function that invokes the method at a given key of an object, optionally adding any additional supplied parameters to the beginning of the arguments.
Next: Write a JavaScript program to chain asynchronous functions.

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JavaScript: Tips of the Day

Returns an array of n-tuples of consecutive elements

Example:

const tips_arr = (n, arr) =>  n > arr.length ? [] : arr.slice(n - 1).map((v, i) =>[...arr.slice(i, i + n - 1), v]);
console.log(tips_arr(2, [1, 2, 3, 4, 5])); 
console.log(tips_arr(3, [1, 2, 3, 4, 5]));
console.log(tips_arr(5, [1, 2, 3, 4]));

Output:

[[1, 2], [2, 3], [3, 4], [4, 5]]
[[1, 2, 3], [2, 3, 4], [3, 4, 5]]
[]