Blockly.JavaScript[''] = function()

in generators/javascript/text.js [180:254]

• 68 lines of code
• 24 McCabe index (conditional complexity)

Blockly.JavaScript['text_getSubstring'] = function(block) {
  // Get substring.
  var where1 = block.getFieldValue('WHERE1');
  var where2 = block.getFieldValue('WHERE2');
  var requiresLengthCall = (where1 != 'FROM_END' && where1 != 'LAST' &&
      where2 != 'FROM_END' && where2 != 'LAST');
  var textOrder = requiresLengthCall ? Blockly.JavaScript.ORDER_MEMBER :
      Blockly.JavaScript.ORDER_NONE;
  var text = Blockly.JavaScript.valueToCode(block, 'STRING',
      textOrder) || '\'\'';
  if (where1 == 'FIRST' && where2 == 'LAST') {
    var code = text;
    return [code, Blockly.JavaScript.ORDER_NONE];
  } else if (text.match(/^'?\w+'?$/) || requiresLengthCall) {
    // If the text is a variable or literal or doesn't require a call for
    // length, don't generate a helper function.
    switch (where1) {
      case 'FROM_START':
        var at1 = Blockly.JavaScript.getAdjusted(block, 'AT1');
        break;
      case 'FROM_END':
        var at1 = Blockly.JavaScript.getAdjusted(block, 'AT1', 1, false,
            Blockly.JavaScript.ORDER_SUBTRACTION);
        at1 = text + '.length - ' + at1;
        break;
      case 'FIRST':
        var at1 = '0';
        break;
      default:
        throw Error('Unhandled option (text_getSubstring).');
    }
    switch (where2) {
      case 'FROM_START':
        var at2 = Blockly.JavaScript.getAdjusted(block, 'AT2', 1);
        break;
      case 'FROM_END':
        var at2 = Blockly.JavaScript.getAdjusted(block, 'AT2', 0, false,
            Blockly.JavaScript.ORDER_SUBTRACTION);
        at2 = text + '.length - ' + at2;
        break;
      case 'LAST':
        var at2 = text + '.length';
        break;
      default:
        throw Error('Unhandled option (text_getSubstring).');
    }
    code = text + '.slice(' + at1 + ', ' + at2 + ')';
  } else {
    var at1 = Blockly.JavaScript.getAdjusted(block, 'AT1');
    var at2 = Blockly.JavaScript.getAdjusted(block, 'AT2');
    var getIndex_ = Blockly.JavaScript.text.getIndex_;
    var wherePascalCase = {'FIRST': 'First', 'LAST': 'Last',
      'FROM_START': 'FromStart', 'FROM_END': 'FromEnd'};
    var functionName = Blockly.JavaScript.provideFunction_(
        'subsequence' + wherePascalCase[where1] + wherePascalCase[where2],
        ['function ' + Blockly.JavaScript.FUNCTION_NAME_PLACEHOLDER_ +
        '(sequence' +
        // The value for 'FROM_END' and'FROM_START' depends on `at` so
        // we add it as a parameter.
        ((where1 == 'FROM_END' || where1 == 'FROM_START') ? ', at1' : '') +
        ((where2 == 'FROM_END' || where2 == 'FROM_START') ? ', at2' : '') +
        ') {',
          '  var start = ' + getIndex_('sequence', where1, 'at1') + ';',
          '  var end = ' + getIndex_('sequence', where2, 'at2') + ' + 1;',
          '  return sequence.slice(start, end);',
          '}']);
    var code = functionName + '(' + text +
        // The value for 'FROM_END' and 'FROM_START' depends on `at` so we
        // pass it.
        ((where1 == 'FROM_END' || where1 == 'FROM_START') ? ', ' + at1 : '') +
        ((where2 == 'FROM_END' || where2 == 'FROM_START') ? ', ' + at2 : '') +
        ')';
  }
  return [code, Blockly.JavaScript.ORDER_FUNCTION_CALL];
};