What's the best way to convert a number to a string in JavaScript? [closed]

Answer 1

It seems similar results when using node.js. I ran this script:

let bar;
let foo = ["45","foo"];

console.time('string concat testing');
for (let i = 0; i < 10000000; i++) {
    bar = "" + foo;
}
console.timeEnd('string concat testing');


console.time("string obj testing");
for (let i = 0; i < 10000000; i++) {
    bar = String(foo);
}
console.timeEnd("string obj testing");

console.time("string both");
for (let i = 0; i < 10000000; i++) {
    bar = "" + foo + "";
}
console.timeEnd("string both");

and got the following results:

❯ node testing.js
string concat testing: 2802.542ms
string obj testing: 3374.530ms
string both: 2660.023ms

Similar times each time I ran it.

Answer 2

With number literals, the dot for accessing a property must be distinguished from the decimal dot. This leaves you with the following options if you want to invoke to String() on the number literal 123:

123..toString()
123 .toString() // space before the dot 123.0.toString()
(123).toString()

Answer 3

.toString() is the built-in typecasting function, I'm no expert to that details but whenever we compare built-in type casting verse explicit methodologies, built-in workarounds always preferred.

Answer 4

...JavaScript's parser tries to parse the dot notation on a number as a floating point literal.

2..toString(); // the second point is correctly recognized
2 .toString(); // note the space left to the dot
(2).toString(); // 2 is evaluated first

Source

Answer 5

The simplest way to convert any variable to a string is to add an empty string to that variable.

5.41 + ''    // Result: the string '5.41'
Math.PI + '' // Result: the string '3.141592653589793'