flow like the river

VISUALIZACION/node_modules/graphql/language/blockString.js.flow

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+// @flow strict
+/**
+ * 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.
+ *
+ * @internal
+ */
+export function dedentBlockStringValue(rawString: string): string {
+  // Expand a block string's raw value into independent lines.
+  const lines = rawString.split(/\r\n|[\n\r]/g);
+
+  // Remove common indentation from all lines but first.
+  const commonIndent = getBlockStringIndentation(rawString);
+
+  if (commonIndent !== 0) {
+    for (let i = 1; i < lines.length; i++) {
+      lines[i] = lines[i].slice(commonIndent);
+    }
+  }
+
+  // Remove leading and trailing blank lines.
+  let startLine = 0;
+  while (startLine < lines.length && isBlank(lines[startLine])) {
+    ++startLine;
+  }
+
+  let endLine = lines.length;
+  while (endLine > startLine && isBlank(lines[endLine - 1])) {
+    --endLine;
+  }
+
+  // Return a string of the lines joined with U+000A.
+  return lines.slice(startLine, endLine).join('\n');
+}
+
+function isBlank(str: string): boolean {
+  for (let i = 0; i < str.length; ++i) {
+    if (str[i] !== ' ' && str[i] !== '\t') {
+      return false;
+    }
+  }
+
+  return true;
+}
+
+/**
+ * @internal
+ */
+export function getBlockStringIndentation(value: string): number {
+  let isFirstLine = true;
+  let isEmptyLine = true;
+  let indent = 0;
+  let commonIndent = null;
+
+  for (let i = 0; i < value.length; ++i) {
+    switch (value.charCodeAt(i)) {
+      case 13: //  \r
+        if (value.charCodeAt(i + 1) === 10) {
+          ++i; // skip \r\n as one symbol
+        }
+      // falls through
+      case 10: //  \n
+        isFirstLine = false;
+        isEmptyLine = true;
+        indent = 0;
+        break;
+      case 9: //   \t
+      case 32: //  <space>
+        ++indent;
+        break;
+      default:
+        if (
+          isEmptyLine &&
+          !isFirstLine &&
+          (commonIndent === null || indent < commonIndent)
+        ) {
+          commonIndent = indent;
+        }
+        isEmptyLine = false;
+    }
+  }
+
+  return commonIndent ?? 0;
+}
+
+/**
+ * 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.
+ *
+ * @internal
+ */
+export function printBlockString(
+  value: string,
+  indentation: string = '',
+  preferMultipleLines: boolean = false,
+): string {
+  const isSingleLine = value.indexOf('\n') === -1;
+  const hasLeadingSpace = value[0] === ' ' || value[0] === '\t';
+  const hasTrailingQuote = value[value.length - 1] === '"';
+  const hasTrailingSlash = value[value.length - 1] === '\\';
+  const printAsMultipleLines =
+    !isSingleLine ||
+    hasTrailingQuote ||
+    hasTrailingSlash ||
+    preferMultipleLines;
+
+  let 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, '\\"""') + '"""';
+}