Unify 'print' and 'printSchema' output for block strings

Author: IvanGoncharov

src/language/__tests__/schema-printer-test.js

@@ -54,18 +54,12 @@ describe('Printer: SDL document', () => {
       type Foo implements Bar & Baz {
         "Description of the \`one\` field."
         one: Type
-        """
-        This is a description of the \`two\` field.
-        """
+        """This is a description of the \`two\` field."""
         two(
-          """
-          This is a description of the \`argument\` argument.
-          """
+          """This is a description of the \`argument\` argument."""
           argument: InputType!
         ): Type
-        """
-        This is a description of the \`three\` field.
-        """
+        """This is a description of the \`three\` field."""
         three(argument: InputType, other: String): Int
         four(argument: String = "string"): String
         five(argument: [String] = ["string", "string"]): String
@@ -121,13 +115,9 @@ describe('Printer: SDL document', () => {
       extend scalar CustomScalar @onScalar
 
       enum Site {
-        """
-        This is a description of the \`DESKTOP\` value
-        """
+        """This is a description of the \`DESKTOP\` value"""
         DESKTOP
-        """
-        This is a description of the \`MOBILE\` value
-        """
+        """This is a description of the \`MOBILE\` value"""
         MOBILE
         "This is a description of the \`WEB\` value"
         WEB
@@ -163,9 +153,7 @@ describe('Printer: SDL document', () => {
 
       extend input InputType @onInputObject
 
-      """
-      This is a description of the \`@skip\` directive
-      """
+      """This is a description of the \`@skip\` directive"""
       directive @skip(if: Boolean! @onArgumentDefinition) on FIELD | FRAGMENT_SPREAD | INLINE_FRAGMENT
 
       directive @include(if: Boolean!) on FIELD | FRAGMENT_SPREAD | INLINE_FRAGMENT

src/language/blockStringValue.js

@@ -62,3 +62,32 @@ function leadingWhitespace(str) {
 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.
+ */
+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 printAsMultipleLines =
+    !isSingleLine || hasTrailingQuote || 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, '\\"""') + '"""';
+}

src/language/printer.js

@@ -9,6 +9,7 @@
 
 import type { ASTNode } from './ast';
 import { visit } from './visitor';
+import { printBlockString } from './blockStringValue';
 
 /**
  * Converts an AST into a string, using one set of reasonable
@@ -90,7 +91,7 @@ const printDocASTReducer: any = {
   FloatValue: ({ value }) => value,
   StringValue: ({ value, block: isBlockString }, key) =>
     isBlockString
-      ? printBlockString(value, key === 'description')
+      ? printBlockString(value, key === 'description' ? '' : '  ')
       : JSON.stringify(value),
   BooleanValue: ({ value }) => (value ? 'true' : 'false'),
   NullValue: () => 'null',
@@ -273,15 +274,3 @@ function isMultiline(string) {
 function hasMultilineItems(maybeArray) {
   return maybeArray && maybeArray.some(isMultiline);
 }
-
-/**
- * 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, isDescription) {
-  const escaped = value.replace(/"""/g, '\\"""');
-  return isMultiline(value) || (value[0] !== ' ' && value[0] !== '\t')
-    ? `"""\n${isDescription ? escaped : indent(escaped)}\n"""`
-    : `"""${escaped.replace(/"$/, '"\n')}"""`;
-}

src/utilities/schemaPrinter.js

@@ -12,6 +12,7 @@ import objectValues from '../polyfills/objectValues';
 import inspect from '../jsutils/inspect';
 import { astFromValue } from '../utilities/astFromValue';
 import { print } from '../language/printer';
+import { printBlockString } from '../language/blockStringValue';
 import type { GraphQLSchema } from '../type/schema';
 import {
   isScalarType,
@@ -329,37 +330,13 @@ function printDescription(
     return printDescriptionWithComments(lines, indentation, firstInBlock);
   }
 
-  let description =
-    indentation && !firstInBlock
-      ? '\n' + indentation + '"""'
-      : indentation + '"""';
-
-  // In some circumstances, a single line can be used for the description.
-  if (
-    lines.length === 1 &&
-    lines[0].length < 70 &&
-    lines[0][lines[0].length - 1] !== '"'
-  ) {
-    return description + escapeQuote(lines[0]) + '"""\n';
-  }
-
-  // Format a multi-line block quote to account for leading space.
-  const hasLeadingSpace = lines[0][0] === ' ' || lines[0][0] === '\t';
-  if (!hasLeadingSpace) {
-    description += '\n';
-  }
-  for (let i = 0; i < lines.length; i++) {
-    if (i !== 0 || !hasLeadingSpace) {
-      description += indentation;
-    }
-    description += escapeQuote(lines[i]) + '\n';
-  }
-  description += indentation + '"""\n';
-  return description;
-}
+  const text = lines.join('\n');
+  const preferMultipleLines = text.length > 70;
+  const blockString = printBlockString(text, '', preferMultipleLines);
+  const prefix =
+    indentation && !firstInBlock ? '\n' + indentation : indentation;
 
-function escapeQuote(line) {
-  return line.replace(/"""/g, '\\"""');
+  return prefix + blockString.replace(/\n/g, '\n' + indentation) + '\n';
 }
 
 function printDescriptionWithComments(lines, indentation, firstInBlock) {