Esoteric mutable way

let a= ["Hello", "World"];

while(a.length) { console.log( a.shift() ); }

Esoteric

let a= ["Hello", "World"];

while(a.length) { console.log( a.shift() ); }

Performance test

Today (2022-11-13) I perform a test on Chrome 107, Safari 15.2 and Firefox 106 on chosen solutions.

Conclusions

• solutions C and D are fast or fastest on all browsers for all arrays.
• solution A and B are slowest on all browsers for all arrays

Results

Details

I perform 3 tests:

• small - for 2 elements array (like OP) - you can run it here
• medium - for 10K elements array and - you can run it here
• big - for 100K elements array - you can run it here

The below snippet presents code used in the test.

function A(a) {
  let r=0;
  while(a.length) r+= a.shift().length;
  return r;
}

function B(a) {
  let r=0;
  for(i in a) r+= a[i].length;
  return r;
}

function C(a) {
  let r=0;
  for(x of a) r+= x.length;
  return r;
}

function D(a) {
  let r=0;
  for (i=0; i<a.length; ++i) r+= a[i].length;
  return r;

}

function E(a) {
  let r=0;
  a.forEach(x=> r+= x.length);
  return r;
}

let arr= ["Hello", "World!"];
[A,B,C,D,E].forEach(f => console.log(`${f.name}: ${f([...arr])}`))

Here are example results for Chrome for a medium array:

Esoteric, but fast

let a= ["Hello", "World"];

while(a.length) { console.log( a.shift() ); }

Performance test

Today (2020-08-05) I perform a test on Chrome 84, Safari 13 and Firefox 78 on chosen solutions.

Conclusions

• while solution (A) is the fastest on all browsers for all arrays except the big one on Chrome (which is surprising).
• for medium arrays the while solution (A) is thousands of times faster than other solutions (!!!)
• The while solution (A) slows down on Chrome for arrays witch 30-40k elements
• The for-in solution (B) is slowest

Results

Details

I perform 3 tests:

• small - for 2 elements array (like OP) - you can run it here
• medium - for 10K elements array and - you can run it here
• big - for 100K elements array - you can run it here

The below snippet presents code used in the test.

function A(a) {
  let r=0;
  while(a.length) r+= a.shift().length;
  return r;
}

function B(a) {
  let r=0;
  for(i in a) r+= a[i].length;
  return r;
}

function C(a) {
  let r=0;
  for(x of a) r+= x.length;
  return r;
}

function D(a) {
  let r=0;
  for (i=0; i<a.length; ++i) r+= a[i].length;
  return r;

}

function E(a) {
  let r=0;
  a.forEach(x=> r+= x.length);
  return r;
}

let arr= ["Hello", "World!"];
[A,B,C,D,E].forEach(f => console.log(`${f.name}: ${f([...arr])}`))

Here are example results for Chrome for a medium array:

Esoteric mutable way

let a= ["Hello", "World"];

while(a.length) { console.log( a.shift() ); }

Esoteric but fast

let a= ["Hello", "World"];

while(a.length) { console.log( a.shift() ); }

Performance test

Today (2020-08-05) I perform test on Chrome 84, Safari 13 and Firefox 78 on chosen solutions.

Conclusions

• while solution (A) is fastest on all browser for all arrays except big one on Chrome (which is surprising).
• for medium arrays while solution (A) is thousands of times faster than other solutions (!!!)
• while solution (A) slows down on chrome for arrays witch 30-40k elements
• for-in solution (B) is slowest

Results

Details

I perform 3 tests:

• small - for 2 elements array (like OP) - you can run it here
• medium - for 10K elements array and - you can run it here
• big - for 100K elements array - you can run it here

Below snippet presents code used in test

function A(a) {
  let r=0;
  while(a.length) r+= a.shift().length;
  return r;
}

function B(a) {
  let r=0;
  for(i in a) r+= a[i].length;
  return r;
}

function C(a) {
  let r=0;
  for(x of a) r+= x.length;
  return r;
}

function D(a) {
  let r=0;
  for (i=0; i<a.length; ++i) r+= a[i].length;
  return r;

}

function E(a) {
  let r=0;
  a.forEach(x=> r+= x.length);
  return r;
}

let arr= ["Hello", "World!"];
[A,B,C,D,E].forEach(f => console.log(`${f.name}: ${f([...arr])}`))

Here are example results for Chrome for medium array

Esoteric, but fast

let a= ["Hello", "World"];

while(a.length) { console.log( a.shift() ); }

Performance test

Today (2020-08-05) I perform a test on Chrome 84, Safari 13 and Firefox 78 on chosen solutions.

Conclusions

• while solution (A) is the fastest on all browsers for all arrays except the big one on Chrome (which is surprising).
• for medium arrays the while solution (A) is thousands of times faster than other solutions (!!!)
• The while solution (A) slows down on Chrome for arrays witch 30-40k elements
• The for-in solution (B) is slowest

Results

Details

I perform 3 tests:

• small - for 2 elements array (like OP) - you can run it here
• medium - for 10K elements array and - you can run it here
• big - for 100K elements array - you can run it here

The below snippet presents code used in the test.

function A(a) {
  let r=0;
  while(a.length) r+= a.shift().length;
  return r;
}

function B(a) {
  let r=0;
  for(i in a) r+= a[i].length;
  return r;
}

function C(a) {
  let r=0;
  for(x of a) r+= x.length;
  return r;
}

function D(a) {
  let r=0;
  for (i=0; i<a.length; ++i) r+= a[i].length;
  return r;

}

function E(a) {
  let r=0;
  a.forEach(x=> r+= x.length);
  return r;
}

let arr= ["Hello", "World!"];
[A,B,C,D,E].forEach(f => console.log(`${f.name}: ${f([...arr])}`))

Here are example results for Chrome for a medium array: