JavaScript: Conversion of integers to English words

JavaScript Math: Exercise-105 with Solution

Write a JavaScript program that converts a non-negative integer number to its English representation.

Test Data:
(1002) -> One Thousand Two.
(1279) -> One Thousand Two Hundred Seventy Nine.
(127900) -> One Hundred Twenty Seven Thousand Nine Hundred.
(1279000) -> One Million Two Hundred Seventy Nine Thousand.

Sample Solution:

JavaScript Code:

/**
 * Function to convert a given number into words.
 * @param {number} n - The number to be converted into words.
 * @returns {string} - The word representation of the given number.
 */
function test(n) {
    if (n < 0)
        return false;
    
    // Arrays to hold words for single-digit, double-digit, and below-hundred numbers
    single_digit = ['', 'One', 'Two', 'Three', 'Four', 'Five', 'Six', 'Seven', 'Eight', 'Nine']
    double_digit = ['Ten', 'Eleven', 'Twelve', 'Thirteen', 'Fourteen', 'Fifteen', 'Sixteen', 'Seventeen', 'Eighteen', 'Nineteen']
    below_hundred = ['Twenty', 'Thirty', 'Forty', 'Fifty', 'Sixty', 'Seventy', 'Eighty', 'Ninety']
    
    if (n === 0) return 'Zero';
    
    // Recursive function to translate the number into words
    function translate(n) {
        let word = "";
        if (n < 10) {
            word = single_digit[n] + ' ';
        } else if (n < 20) {
            word = double_digit[n - 10] + ' ';
        } else if (n < 100) {
            let rem = translate(n % 10);
            word = below_hundred[(n - n % 10) / 10 - 2] + ' ' + rem;
        } else if (n < 1000) {
            word = single_digit[Math.trunc(n / 100)] + ' Hundred ' + translate(n % 100);
        } else if (n < 1000000) {
            word = translate(parseInt(n / 1000)).trim() + ' Thousand ' + translate(n % 1000);
        } else if (n < 1000000000) {
            word = translate(parseInt(n / 1000000)).trim() + ' Million ' + translate(n % 1000000);
        } else {
            word = translate(parseInt(n / 1000000000)).trim() + ' Billion ' + translate(n % 1000000000);
        }
        return word;
    }
    
    // Get the result by translating the given number
    let result = translate(n);
    return result.trim() + '.';
}

n = 1002;
console.log("Number n = " + n);
console.log("In word: " + test(n));
n = 1279;
console.log("Number n = " + n);
console.log("In word: " + test(n));
n = 127900;
console.log("Number n = " + n);
console.log("In word: " + test(n));
n = 1279000;
console.log("Number n = " + n);
console.log("In word: " + test(n));

Output:

Number n = 1002
In word: One Thousand Two.
Number n = 1279
In word: One Thousand Two Hundred Seventy Nine.
Number n = 127900
In word: One Hundred Twenty Seven Thousand Nine Hundred.
Number n = 1279000
In word: One Million Two Hundred Seventy Nine Thousand.

Flowchart:

Live Demo:

See the Pen javascript-math-exercise-105 by w3resource (@w3resource) on CodePen.

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