JavaScript: Get the first non-null / undefined argument

JavaScript fundamental (ES6 Syntax): Exercise-64 with Solution

Get First Non-Null/Undefined Argument

Write a JavaScript program to get the first non-null / undefined argument.

• Use Array.prototype.find() and Array.prototype.includes() to find the first value that is not equal to undefined or null.

Sample Solution:

JavaScript Code:

//#Source https://bit.ly/2neWfJ2
// Define a function 'coalesce' to return the first non-null and non-undefined value from the provided arguments.
const coalesce = (...args) => args.find(_ => ![undefined, null].includes(_));

// Test the 'coalesce' function with various arguments including null, undefined, empty string, NaN, and a string.
console.log(coalesce(null, undefined, '', NaN, 'abcd')); // Output the first non-null and non-undefined value.

Flowchart:

Live Demo:

See the Pen javascript-basic-exercise-64-1 by w3resource (@w3resource) on CodePen.

For more Practice: Solve these Related Problems:

• Write a JavaScript program that returns the first argument from a list that is not null or undefined.
• Write a JavaScript function that iterates over its arguments and returns the first value that is truthy according to a custom check.
• Write a JavaScript program that simulates a coalesce operator by selecting the first defined argument from a set.

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