How to convert numbers to string in JavaScript

We can convert a number to a string in 3 ways:

  • Using the toString method
  • Using the String() constructor
  • Concatenating the Number with an empty string

Using toString

We can use the toString method to convert numbers to String. Make sure the number is not undefined or null.

let a = 100;
console.log("Converting 100 to string", a.toString());
let floatingNum = 100.12200;
console.log("Converting 100.12200 to string", floatingNum.toString());
console.log("Converting NaN to string", NaN.toString());
try{
    console.log("\n------\ncalling toString on null");
    (null).toString(); //error
} catch(e) {
    console.log(e.message);
}
try{
    console.log("\n-----\ncalling toString on undefined");
    (undefined).toString(); //error
} catch(e) {
    console.log(e.message);
}

Using the String() constructor

We can use the String() constructor to convert a number to a string. When null or undefined is passed, then null and undefined Strings will be returned (respectively).

let num = 10;
console.log("Conveting 10 to String =", String(num));
let floatingNum = 20.12200;
console.log("Conveting 20.12200 to String =", String(floatingNum));
console.log("Conveting undefined to String =", String(undefined));
console.log("Conveting null to String =", String(null));
console.log("Conveting NaN to String =", String(NaN));

Concatenating the number with an empty string

By adding an empty string, the number will internally be converted to String.

let num = 10;
console.log("Conveting 10 to String =", (num + '') );
let floatingNum = 20.12200;
console.log("Conveting 20.12200 to String =", (floatingNum + ''));
console.log("Conveting undefined to String =", (undefined + ''));
console.log("Conveting null to String =", (null + '') );
console.log("Conveting NaN to String =", (NaN + ''));

In addition to the above methods, we can use template a literal to convert a number to String. Use ＄{num} to convert a number to String.

let num = 10;
// `${}`
console.log("Conveting 10 to String =", `${num}` );
let floatingNum = 20.12200;
console.log("Conveting 20.12200 to String =", `${floatingNum}`);
console.log("Conveting undefined to String =", `${undefined}` );
console.log("Conveting null to String =", `${null}` );
console.log("Conveting NaN to String =", `${NaN}`);

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