Function compareCollationElements

packages/intl-collator/compare.ts:418–446

(
  left: readonly PackedCollationElement[],
  right: readonly PackedCollationElement[],
  levels: number,
  ignoreVariable: boolean
)

}

function compareCollationElements(
  left: readonly PackedCollationElement[],
  right: readonly PackedCollationElement[],
  levels: number,
  ignoreVariable: boolean
): number {
  // UCA compares level by level. ignorePunctuation maps to shifted handling for
  // variable elements, approximated here by filtering variable weights.
  // https://www.unicode.org/reports/tr10/#Multi_Level_Comparison
  // https://www.unicode.org/reports/tr35/tr35-collation.html#Setting_Options
  for (let level = 0; level < levels; level++) {
    const leftWeights = left
      .filter(element => !ignoreVariable || (element[4] & 1) === 0)
      .map(element => element[level])
      .filter(weight => weight !== 0)
    const rightWeights = right
      .filter(element => !ignoreVariable || (element[4] & 1) === 0)
      .map(element => element[level])
      .filter(weight => weight !== 0)
    const length = Math.max(leftWeights.length, rightWeights.length)
    for (let i = 0; i < length; i++) {
      const result = compareNumbers(leftWeights[i] || 0, rightWeights[i] || 0)
      if (result) {
        return result
      }
    }
  }
  return 0
}

function comparePreparedStrings(
  left: string,