What's the best way to convert a number to a s

Question

What's the "best" way to convert a number to a string (in terms of speed advantage, clarity advantage, memory advantage, etc) ?

Some examples:

1. String(n)

2. n.toString()

3. ""+n

4. n+""

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

I'm going to re-edit this with more data when I have time to, for right now this is fine...

Test in nodejs v8.11.2: 2018/06/06

let i=0;
    console.time("test1")
    for(;i<10000000;i=i+1){
    	const string = "" + 1234;
    }
    console.timeEnd("test1")
    
    i=0;
    console.time("test1.1")
    for(;i<10000000;i=i+1){
    	const string = '' + 1234;
    }
    console.timeEnd("test1.1")
    
    i=0;
    console.time("test1.2")
    for(;i<10000000;i=i+1){
    	const string = `` + 1234;
    }
    console.timeEnd("test1.2")
    
    i=0;
    console.time("test1.3")
    for(;i<10000000;i=i+1){
    	const string = 1234 +  '';
    }
    console.timeEnd("test1.3")
    
    
    i=0;
    console.time("test2")
    for(;i<10000000;i=i+1){
    	const string = (1234).toString();
    }
    console.timeEnd("test2")
    
    
    i=0;
    console.time("test3")
    for(;i<10000000;i=i+1){
    	const string = String(1234);
    }
    console.timeEnd("test3")
    
    
    i=0;
    console.time("test4")
    for(;i<10000000;i=i+1){
    	const string = `${1234}`;
    }
    console.timeEnd("test4")
    
    i=0;
    console.time("test5")
    for(;i<10000000;i=i+1){
    	const string = 1234..toString();
    }
    console.timeEnd("test5")
    
    i=0;
    console.time("test6")
    for(;i<10000000;i=i+1){
    	const string = 1234 .toString();
    }
    console.timeEnd("test6")

output

test1: 72.268ms
test1.1: 61.086ms
test1.2: 66.854ms
test1.3: 63.698ms
test2: 207.912ms
test3: 81.987ms
test4: 59.752ms
test5: 213.136ms
test6: 204.869ms

Answer 3

If I had to take everything into consideration, I will suggest following

var myint = 1;
var mystring = myint + '';
/*or int to string*/
myint = myint + ''

IMHO, its the fastest way to convert to string. Correct me if I am wrong.

Answer 4

We can also use the String constructor. According to this benchmark it's the fastest way to convert a Number to String in Firefox 58 even though it's slower than " + num in the popular browser Google Chrome.

Answer 5

I used https://jsperf.com to create a test case for the following cases:

number + ''
`${number}`
String(number)
number.toString()

https://jsperf.com/number-string-conversion-speed-comparison

As of 24th of July, 2018 the results say that number + '' is the fastest in Chrome, in Firefox that ties with template string literals.

Both String(number), and number.toString() are around 95% slower than the fastest option.

Answer 6

I like the first two since they're easier to read. I tend to use String(n) but it is just a matter of style than anything else.

That is unless you have a line as

var n = 5;
console.log ("the number is: " + n);

which is very self explanatory