Function listPatternFormatter

index.js:44–104

(list, _config)

}

function listPatternFormatter(list, _config) {
  // Use the default config patternType by default…
  var patternTypeResolution = this.__config__.patternType;

  // If we're overriding the pattern type just for this format call, do it
  if (_config && _config.patternType) {
    patternTypeResolution = _config.patternType;
  }

  var listPatternRules =
    this.__cldr__[LIST_PATTERN_PREFIX + patternTypeResolution] ||
    this.__cldr__[LIST_PATTERN_PREFIX + this.__config__.patternType] ||
    this.__cldr__[LIST_PATTERN_PREFIX + DEFAULT_LIST_PATTERN];

  if (!listPatternRules) {
    throw new Error('Unable to find a valid list pattern or fallback pattern.');
  }

  // Check for literal length rules
  if (listPatternRules.hasOwnProperty(list.length + '')) {
    return formatLiteralPattern(list, listPatternRules[list.length + '']);
  }

  // If we're here, we've got a standard "start" "middle" "end" situation
  var result = '';

  // This is the "correct" output, but if someone got here, they probably
  // already wanted to handle the empty case.
  if (list.length < 1) {
    return '';
  }

  // This is also a 'silent failure' mode, but ideally handled externally
  if (list.length === 1) {
    return list[0];
  }

  // Start with end
  var pointer = list.length - 1;
  result = listPatternRules.end
    .replace('{1}', list[pointer])
    .replace('{0}', list[pointer - 1]);

  // We used up 2 indexes already
  pointer = pointer - 2;

  // Fill in the middle section
  while (pointer > 0) {
    result = listPatternRules.middle
      .replace('{1}', result)
      .replace('{0}', list[pointer]);
    pointer -= 1;
  }

  // Handle the 'start' base-case
  result = listPatternRules.start
    .replace('{1}', result)
    .replace('{0}', list[pointer]);