JSTests/test262/harness/regExpUtils.js

// Copyright (C) 2017 Mathias Bynens.  All rights reserved.
// This code is governed by the BSD license found in the LICENSE file.
/*---
description: |
    Collection of functions used to assert the correctness of RegExp objects.
defines: [buildString, testPropertyEscapes, matchValidator]
---*/

function buildString({ loneCodePoints, ranges }) {
  const CHUNK_SIZE = 10000;
  let result = Reflect.apply(String.fromCodePoint, null, loneCodePoints);
  for (let i = 0; i < ranges.length; i++) {
    const range = ranges[i];
    const start = range[0];
    const end = range[1];
    const codePoints = [];
    for (let length = 0, codePoint = start; codePoint <= end; codePoint++) {
      codePoints[length++] = codePoint;
      if (length === CHUNK_SIZE) {
        result += Reflect.apply(String.fromCodePoint, null, codePoints);
        codePoints.length = length = 0;
      }
    }
    result += Reflect.apply(String.fromCodePoint, null, codePoints);
  }
  return result;
}

function testPropertyEscapes(regex, string, expression) {
  if (!regex.test(string)) {
    for (const symbol of string) {
      const hex = symbol
        .codePointAt(0)
        .toString(16)
        .toUpperCase()
        .padStart(6, "0");
      assert(
        regex.test(symbol),
        `\`${ expression }\` should match U+${ hex } (\`${ symbol }\`)`
      );
    }
  }
}

// Returns a function that will validate RegExp match result
//
// Example:
//
//    var validate = matchValidator(['b'], 1, 'abc');
//    validate(/b/.exec('abc'));
//
function matchValidator(expectedEntries, expectedIndex, expectedInput) {
  return function(match) {
    assert.compareArray(match, expectedEntries, 'Match entries');
    assert.sameValue(match.index, expectedIndex, 'Match index');
    assert.sameValue(match.input, expectedInput, 'Match input');
  }
}