Benchmark: Trim by RegExp - MeasureThat.net

Script Preparation code:

//No backtracking trim RegExp, captures whitespace:

var _trim1RE = /^(\s*)(?:\S*(\s*))+?$/;
function trim1(string) {
  var m = _trim1RE.exec(string);
  return string.substring(m[1].length, string.length - m[2].length);
}

//Direct trim RegExp with very minimal backtracking.

var _trim2RE = /\S+(?:\s+?\S+)*/;
function trim2(string) {
  var m = _trim2RE.exec(string);
  return m ? m[0] : "";  // Doesn't match => there is no non-whitespace in string.
}

var _trim3RE = /^(\s*)(?:\S+(\s*))*?$/;
function trim3(string) {
  var m = _trim3RE.exec(string);
  return string.substring(m[1].length, string.length - (m[2]||"").length);
}

var long = "          ";
long += long; // 20
long += long; // 40
long += long; // 80
long += long; // 160
long += long; // 320
long += long; // 640
long += long; // 1280
long += long; // 2560
long += long; // 5102
long += long; // 10240
long += long; // 20480

var prelong = long + "a";
var postlong = "a" + long;
var midlong = "a" + long + "a";

function bench(trim) {
  for (var i = 0; i < 1000; i++) {
    trim("    abcdefgh    ");
    trim("                ");
    trim(" a            b ");
    trim("a              a");
  }
  trim(long);
  trim(prelong);
  trim(postlong);
  trim(midlong);
}

Tests:

/^(\s*)(?:\S*(\s*))+?$/
bench(trim1);
/\S+(?:\s+?\S+)*/
bench(trim2);
/^(\s*)(?:\S+(\s*))*?$/
bench(trim3);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
/^(\s)(?:\S(\s*))+?$/
/\S+(?:\s+?\S+)*/
/^(\s)(?:\S+(\s))*?$/

Fastest: N/A

Slowest: N/A

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Latest run results:

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Trim by RegExp (version: 1)

Comparing performance of: /^(\s)(?:\S(\s))+?$/ vs /\S+(?:\s+?\S+)/ vs /^(\s)(?:\S+(\s))*?$/

Created: 7 years ago by: Registered User

Jump to the latest result

/^(\s)(?:\S(\s*))+?$/

/\S+(?:\s+?\S+)*/

/^(\s)(?:\S+(\s))*?$/

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

No previous run results

Trim by RegExp (version: 1)

Comparing performance of: /^(\s*)(?:\S*(\s*))+?$/ vs /\S+(?:\s+?\S+)*/ vs /^(\s*)(?:\S+(\s*))*?$/

Created: 7 years ago by: Registered User

Jump to the latest result

/^(\s*)(?:\S*(\s*))+?$/

/\S+(?:\s+?\S+)*/

/^(\s*)(?:\S+(\s*))*?$/

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

No previous run results

Comparing performance of: /^(\s)(?:\S(\s))+?$/ vs /\S+(?:\s+?\S+)/ vs /^(\s)(?:\S+(\s))*?$/

/^(\s)(?:\S(\s*))+?$/

/^(\s)(?:\S+(\s))*?$/