JavaScript: Check whether the provided argument is array-like

JavaScript fundamental (ES6 Syntax): Exercise-205 with Solution

Check If Array

Write a JavaScript program to check if the provided argument is an array (i.e. iterable).

• Check if the provided argument is not null and that its Symbol.iterator property is a function.

Sample Solution:

JavaScript Code:

// Define a function 'isArrayLike' that checks if the input value is array-like
const isArrayLike = val => {
  try {
    return [...val], true; // Try to spread the input value into an array and return true
  } catch (e) {
    return false; // If an error occurs, return false
  }
};

// Test cases to check if the input values are array-like
console.log(isArrayLike(document.querySelectorAll('.className'))); // true (document.querySelectorAll('.className') returns a NodeList which is array-like)
console.log(isArrayLike('abc')); // true ('abc' is a string which is array-like)
console.log(isArrayLike(null)); // false (null is not array-like)

Output:

true
true
false

Flowchart:

Live Demo:

See the Pen javascript-basic-exercise-205-1 by w3resource (@w3resource) on CodePen.

For more Practice: Solve these Related Problems:

• Write a JavaScript program that returns true if the provided argument is an array using Array.isArray().
• Write a JavaScript function that checks if an object is iterable and has a length property indicative of an array.
• Write a JavaScript program that distinguishes arrays from objects by testing the constructor.
• Write a JavaScript function that uses Object.prototype.toString() to confirm if a value is an Array.

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