The Number object's toString() method

The toString() method returns a string representing the specified Number object.

Syntax

numObj.toString([radix])

Parameters

radix (optional):

• An integer between 2 and 36 specifying the base to use for representing the number value

• Default is 10 (decimal) if not specified

• Allows conversion to binary (2), octal (8), hexadecimal (16), or other number systems

Return value

The toString() method returns a string representing the specified Number value.

Examples

Example 1: Basic number to string conversion

In the code below, the function toStringEx1() demonstrates basic number-to-string conversion.

function toStringEx1() {
  let num = 42;
  
  // Basic conversion to string
  Logger.log(num.toString());      // "42"
  Logger.log((3.14159).toString()); // "3.14159"
  
  // String concatenation with numbers
  Logger.log("The answer is " + num); // "The answer is 42" (implicit toString())
  
  // Explicit vs. implicit conversion
  Logger.log(num.toString() === num + ""); // true
  
  // Using toString() on numeric literals requires parentheses
  // Logger.log(42.toString()); // This would cause a syntax error
  Logger.log((42).toString());    // "42" (correct syntax)
  
  // Negative numbers
  Logger.log((-123).toString());  // "-123"
}

Output:

42

3.14159

The answer is 42

true

42

-123

Example 2: Using different radices

In the code below, the function toStringEx2() shows how to convert numbers to strings using different number bases.

function toStringEx2() {
  let num = 42;
  
  // Decimal (base 10) - default
  Logger.log(num.toString(10)); // "42"
  
  // Binary (base 2)
  Logger.log(num.toString(2));  // "101010"
  
  // Octal (base 8)
  Logger.log(num.toString(8));  // "52"
  
  // Hexadecimal (base 16)
  Logger.log(num.toString(16)); // "2a"
  
  // Other bases
  Logger.log(num.toString(36)); // "16" (highest supported base: 0-9, a-z)
  
}

Output:

42

101010

52

2a

16

Example 3: Handling special cases

In the code below, the function toStringEx3() demonstrates handling of special numeric values.

function toStringEx3() {
  // Special numeric values
  Logger.log(NaN.toString());           // "NaN"
  Logger.log(Infinity.toString());      // "Infinity"
  Logger.log((-Infinity).toString());   // "-Infinity"
  
  // Very large or small numbers
  Logger.log((1e21).toString());        // "1e+21" (scientific notation)
  Logger.log((1e-8).toString());        // "1e-8"
  
  // Zero values
  Logger.log((0).toString());           // "0"
  Logger.log((-0).toString());          // "0" (negative zero becomes "0")
  
  // Floating point precision
  Logger.log((0.1 + 0.2).toString());   // "0.30000000000000004" (floating point issue)
}

Output:

NaN

Infinity

-Infinity

1e+21

1e-8

0

0

0.30000000000000004

Example 4: Practical applications in Apps Script

In the code below, the function toStringEx4() demonstrates practical uses of toString() in Google Apps Script.

function toStringEx4() {
  // Formatting spreadsheet row/column numbers
  let columnNumber = 27;
  Logger.log("Column " + columnNumber + " in A1 notation: " + 
             getColumnLetter(columnNumber));  // "AA"
  
  // Converting numbers to hex for color codes
  let red = 255;
  let green = 128;
  let blue = 0;
  let hexColor = "#" + componentToHex(red) + componentToHex(green) + componentToHex(blue);
  Logger.log("RGB(" + red + "," + green + "," + blue + ") as hex: " + hexColor);  // "#ff8000"
  
  // Helper function to convert spreadsheet column number to letter
  function getColumnLetter(column) {
    let temp, letter = '';
    while (column > 0) {
      temp = (column - 1) % 26;
      letter = String.fromCharCode(temp + 65) + letter;
      column = (column - temp - 1) / 26;
    }
    return letter;
  }
  
  // Helper function to convert a number component to a 2-digit hex value
  function componentToHex(c) {
    let hex = c.toString(16);
    return hex.length == 1 ? "0" + hex : hex;
  }
}

Output:

Column 27 in A1 notation: AA

RGB(255,128,0) as hex: #ff8000

Example 5: Working with fixed precision and formatting

In the code below, the function toStringEx5() demonstrates how to use toString() with formatting numbers for display.

function toStringEx5() {
  let value = 42.1234;
  
  // Basic toString
  Logger.log(value.toString());  // "42.1234"
  
  // toString() vs toFixed() for decimal precision
  Logger.log(value.toString());        // "42.1234" (full precision)
  Logger.log(value.toFixed(2));        // "42.12" (fixed decimal places)
      
  // Formatting large numbers with thousand separators
  let largeNum = 1234567.89;
  Logger.log(formatNumber(largeNum));  // "1,234,567.89"
  
  // Helper function to format number with thousand separators
  function formatNumber(num) {
    return num.toString().replace(/\B(?=(\d{3})+(?!\d))/g, ",");
  }
}

Output:

42.1234

42.1234

42.12

1,234,567.89

toString() vs String() vs Concatenation

There are multiple ways to convert numbers to strings in JavaScript. Here's how they compare:

function compareStringConversions() {
  let num = 42;
  
  // Method 1: toString() method
  Logger.log(num.toString());  // "42"
  
  // Method 2: String() constructor
  Logger.log(String(num));     // "42"
  
  // Method 3: Concatenation with empty string
  Logger.log(num + "");        // "42"
  
  // Key differences with special values
  Logger.log(String(null));            // "null"
  // Logger.log(null.toString());      // Error: Cannot read property 'toString' of null
  
  Logger.log(String(undefined));       // "undefined"
  // Logger.log(undefined.toString()); // Error: Cannot read property 'toString' of undefined
}

Output:

42

42

42

null

undefined

Common Use Cases

The toString() method for numbers is useful in many scenarios when working with Google Apps Script:

• Data formatting: Converting numeric values to strings for display or reporting.

• Color manipulation: Converting RGB values to hexadecimal color codes.

• Spreadsheet references: Converting row/column numbers to A1 notation.

• Binary operations: Visualizing bit flags or binary data.

• Custom number formatting: Creating formatted strings for currency, percentages, or other numeric representations.

• Base conversion: Converting between different number systems for specialized applications.

Best Practices

When using the toString() method with numbers, keep these tips in mind:

• Remember to use parentheses when calling toString() on numeric literals: (42).toString(), not 42.toString().

• Consider using toFixed() for controlling decimal places when formatting floating-point numbers.

• Use String() constructor instead of toString() when dealing with values that might be null or undefined.

• For complex formatting needs, consider combining toString() with string methods like padStart(), replace(), etc.

Conclusion

In this tutorial, you learned how to use the toString() method to convert numbers to strings in Google Apps Script. You can use toString() to format numeric data for display, perform base conversions, and create custom string representations of numbers in your Apps Script projects.