blockString.js

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.dedentBlockStringValue = dedentBlockStringValue;
exports.getBlockStringIndentation = getBlockStringIndentation;
exports.printBlockString = printBlockString;

/**
 * Produces the value of a block string from its parsed raw value, similar to
 * CoffeeScript's block string, Python's docstring trim or Ruby's strip_heredoc.
 *
 * This implements the GraphQL spec's BlockStringValue() static algorithm.
 */
function dedentBlockStringValue(rawString) {
  // Expand a block string's raw value into independent lines.
  var lines = rawString.split(/\r\n|[\n\r]/g); // Remove common indentation from all lines but first.

  var commonIndent = getBlockStringIndentation(lines);

  if (commonIndent !== 0) {
    for (var i = 1; i < lines.length; i++) {
      lines[i] = lines[i].slice(commonIndent);
    }
  } // Remove leading and trailing blank lines.


  while (lines.length > 0 && isBlank(lines[0])) {
    lines.shift();
  }

  while (lines.length > 0 && isBlank(lines[lines.length - 1])) {
    lines.pop();
  } // Return a string of the lines joined with U+000A.


  return lines.join('\n');
} // @internal


function getBlockStringIndentation(lines) {
  var commonIndent = null;

  for (var i = 1; i < lines.length; i++) {
    var line = lines[i];
    var indent = leadingWhitespace(line);

    if (indent === line.length) {
      continue; // skip empty lines
    }

    if (commonIndent === null || indent < commonIndent) {
      commonIndent = indent;

      if (commonIndent === 0) {
        break;
      }
    }
  }

  return commonIndent === null ? 0 : commonIndent;
}

function leadingWhitespace(str) {
  var i = 0;

  while (i < str.length && (str[i] === ' ' || str[i] === '\t')) {
    i++;
  }

  return i;
}

function isBlank(str) {
  return leadingWhitespace(str) === str.length;
}
/**
 * Print a block string in the indented block form by adding a leading and
 * trailing blank line. However, if a block string starts with whitespace and is
 * a single-line, adding a leading blank line would strip that whitespace.
 */


function printBlockString(value) {
  var indentation = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : '';
  var preferMultipleLines = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : false;
  var isSingleLine = value.indexOf('\n') === -1;
  var hasLeadingSpace = value[0] === ' ' || value[0] === '\t';
  var hasTrailingQuote = value[value.length - 1] === '"';
  var printAsMultipleLines = !isSingleLine || hasTrailingQuote || preferMultipleLines;
  var result = ''; // Format a multi-line block quote to account for leading space.

  if (printAsMultipleLines && !(isSingleLine && hasLeadingSpace)) {
    result += '\n' + indentation;
  }

  result += indentation ? value.replace(/\n/g, '\n' + indentation) : value;

  if (printAsMultipleLines) {
    result += '\n';
  }

  return '"""' + result.replace(/"""/g, '\\"""') + '"""';
}