Numbers and operands to words in JavaScript

We are required to write a JavaScript function that takes in a string of some mathematical operation and return its literal wording.

Problem

Converting mathematical expressions like "5 - 8" into readable words like "Five Minus Eight" requires mapping numbers and operators to their text equivalents.

Approach

We'll create two lookup objects: one for operators and another for numbers. Then parse the input string and convert each part using these mappings.

Example

Following is the code ?

const str = '5 - 8';
const convertToWords = (str = '') => {
    const operators = {
        "+" : "Plus",
        "-" : "Minus", 
        "*" : "Times",
        "/" : "Divided By",
        "**" : "To The Power Of",
        "=" : "Equals",
        "!=" : "Does Not Equal",
    }
    const numbers = {
        1 : "One",
        2 : "Two", 
        3 : "Three",
        4 : "Four",
        5 : "Five",
        6 : "Six",
        7 : "Seven",
        8 : "Eight", 
        9 : "Nine",
        10 : "Ten",
    }
    
    let parts = str.split(' ');
    let result = '';
    let operatorFound = false;
    
    // Check if operator exists
    for (const [key, value] of Object.entries(operators)) {
        if(key === parts[1]) {
            operatorFound = true;
            break;
        }
    }
    
    if(!operatorFound) return "That's not an operator!";
    
    // Convert first number
    for (const [key, value] of Object.entries(numbers)) {
        if(key === parts[0]) {
            result += `${value} `;
        }
    }
    
    // Convert operator
    for (const [key, value] of Object.entries(operators)) {
        if(key === parts[1]) {
            result += `${value}`;
        }
    }
    
    // Convert second number
    for (const [key, value] of Object.entries(numbers)) {
        if(key === parts[2]) {
            result += ` ${value}`;
        }
    }
    
    return result;
}

console.log(convertToWords(str));

Output

Five Minus Eight

Testing Different Operations

console.log(convertToWords('3 + 7'));
console.log(convertToWords('9 * 2'));
console.log(convertToWords('10 / 5'));
console.log(convertToWords('4 ** 3'));

Three Plus Seven
Nine Times Two
Ten Divided By Five
Four To The Power Of Three

How It Works

The function splits the input string by spaces to get three parts: first number, operator, and second number. It uses lookup objects to find the text equivalents and concatenates them into a readable sentence.

Conclusion

This approach effectively converts mathematical expressions to words using object mappings. The function handles various operators and provides clear error messages for invalid inputs.