v8/test/js-perf-test/Strings/string-startswith.js

// Copyright 2019 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

function createSuite(name, count, fn) {
  new BenchmarkSuite(name, [count], [new Benchmark(name, true, false, 0, fn)]);
}

const inputs = [
  'Lorem ipsum dolor sit amet, consectetur adipiscing elit.',
  'Integer eu augue suscipit, accumsan ipsum nec, sagittis sem.',
  'In vitae pellentesque dolor. Curabitur leo nunc, luctus vitae',
  'risus eget, fermentum hendrerit justo.',
  'hello'.repeat(1024),
  'h',
  ''
];
const firsts = ['I', 'Integer', 'Lorem', 'risus', 'hello'];

function simpleHelper() {
  let sum = 0;
  for (const input of inputs) {
    for (const first of firsts) {
      sum += input.startsWith(first);
    }
  }
  return sum;
}

function consInputHelper() {
  let sum = 0;
  for (const inputOne of inputs) {
    for (const inputTwo of inputs) {
      for (const first of firsts) {
        // Skip if the length is too small for %ConstructConsString
        if (inputOne.length + inputTwo.length < 13) break;
        sum += %ConstructConsString(inputOne, inputTwo).startsWith(first);
      }
    }
  }
  return sum;
}

function consFirstHelper() {
  let sum = 0;
  for (const input of inputs) {
    for (const firstOne of firsts) {
      for (const firstTwo of firsts) {
        // Skip if the length is too small for %ConstructConsString
        if (firstOne.length + firstTwo.length < 13) break;
        sum += input.startsWith(%ConstructConsString(firstOne, firstTwo));
      }
    }
  }
  return sum;
}

function doubleConsHelper() {
  let sum = 0;
  for (const inputOne of inputs) {
    for (const inputTwo of inputs) {
      for (const firstOne of firsts) {
        for (const firstTwo of firsts) {
          // Skip if the length is too small for %ConstructConsString
          if (inputOne.length + inputTwo.length < 13 || firstOne.length + firstTwo.length) break;
          sum += % ConstructConsString(inputOne, inputTwo).startsWith(
            % ConstructConsString(firstOne, firstTwo)
          );
        }
      }
    }
  }
}

createSuite('DirectStringsDirectSearch', 1000, simpleHelper);
createSuite('ConsStringsDirectSearch', 1000, consInputHelper);
createSuite('DirectStringsConsSearch', 1000, consFirstHelper);
createSuite('ConsStringsConsSearch', 1000, doubleConsHelper);