Javascript String Concatenation Death Race

Every now and again I get into a discussion with colleagues about the best way to concatenate strings in Javascript. That’s because I live an action packed life.

Developer Alice will say

I think we ought to do it using s + '_' + i

Developer Bob will argue

That’s so last century, do it using *s.concat(‘_’).concat(i)*

Then I will come along and say

We live in the time of Node 8 and so we ought to do it using ${s}_${i}

So let’s try them

Test 1. stringLoopAdd.js

const conTrails = (s, i) => s + '_' + i

for (let i = 0; i < 100000000; i++) conTrails('hello world', i)

Test 2. stringLoopConcat.js

const conTrails = (s, i) => s.concat('_').concat(i)

for (let i = 0; i < 100000000; i++) conTrails('hello world', i)

Test 3. stringLoopES6.js

const conTrails = (s, i) => `${s}_${i}`

for (let i = 0; i < 100000000; i++) conTrails('hello world', i)

Results

Test 1

$ time node stringLoopAdd.js

real 8.107s
user 7.316s
 sys 1.395s

Test 2

$ time node stringLoopConcat.js

real 12.304s
user 11.436s
 sys  1.497s

Test 3

$ time node stringLoopES6.js

real 8.976s
user 8.170s
 sys 1.433s

So there you go. string + string + string wins.

[embed]**“Sometimes the old ways are the best.”**

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