Improve the inspect() function. (#1380)

As well as use it in more places, replace use of JSON.stringify, and ensure validation rule message formatters expect strings instead of types.

src/execution/__tests__/executor-test.js

@@ -1054,7 +1054,7 @@ describe('Execute: Handles basic execution tasks', () => {
       errors: [
         {
           message:
-            'Expected value of type "SpecialType" but got: [object Object].',
+            'Expected value of type "SpecialType" but got: {value: "bar"}.',
           locations: [{ line: 1, column: 3 }],
           path: ['specials', 1],
         },

src/execution/__tests__/variables-test.js

@@ -371,7 +371,7 @@ describe('Execute: Handles inputs', () => {
             {
               message:
                 'Variable "$input" got invalid value ' +
-                '{"a":"foo","b":"bar","c":null}; ' +
+                '{a: "foo", b: "bar", c: null}; ' +
                 'Expected non-nullable type String! not to be null at value.c.',
               locations: [{ line: 2, column: 16 }],
             },
@@ -401,7 +401,7 @@ describe('Execute: Handles inputs', () => {
           errors: [
             {
               message:
-                'Variable "$input" got invalid value {"a":"foo","b":"bar"}; ' +
+                'Variable "$input" got invalid value {a: "foo", b: "bar"}; ' +
                 'Field value.c of required type String! was not provided.',
               locations: [{ line: 2, column: 16 }],
             },
@@ -421,13 +421,13 @@ describe('Execute: Handles inputs', () => {
           errors: [
             {
               message:
-                'Variable "$input" got invalid value {"na":{"a":"foo"}}; ' +
+                'Variable "$input" got invalid value {na: {a: "foo"}}; ' +
                 'Field value.na.c of required type String! was not provided.',
               locations: [{ line: 2, column: 18 }],
             },
             {
               message:
-                'Variable "$input" got invalid value {"na":{"a":"foo"}}; ' +
+                'Variable "$input" got invalid value {na: {a: "foo"}}; ' +
                 'Field value.nb of required type String! was not provided.',
               locations: [{ line: 2, column: 18 }],
             },
@@ -446,7 +446,7 @@ describe('Execute: Handles inputs', () => {
             {
               message:
                 'Variable "$input" got invalid value ' +
-                '{"a":"foo","b":"bar","c":"baz","extra":"dog"}; ' +
+                '{a: "foo", b: "bar", c: "baz", extra: "dog"}; ' +
                 'Field "extra" is not defined by type TestInputObject.',
               locations: [{ line: 2, column: 16 }],
             },
@@ -693,8 +693,8 @@ describe('Execute: Handles inputs', () => {
         errors: [
           {
             message:
-              'Variable "$value" got invalid value [1,2,3]; Expected type ' +
-              'String; String cannot represent an array value: [1,2,3]',
+              'Variable "$value" got invalid value [1, 2, 3]; Expected type ' +
+              'String; String cannot represent an array value: [1, 2, 3]',
             locations: [{ line: 2, column: 16 }],
           },
         ],
@@ -841,7 +841,7 @@ describe('Execute: Handles inputs', () => {
         errors: [
           {
             message:
-              'Variable "$input" got invalid value ["A",null,"B"]; ' +
+              'Variable "$input" got invalid value ["A", null, "B"]; ' +
               'Expected non-nullable type String! not to be null at value[1].',
             locations: [{ line: 2, column: 16 }],
           },
@@ -891,7 +891,7 @@ describe('Execute: Handles inputs', () => {
         errors: [
           {
             message:
-              'Variable "$input" got invalid value ["A",null,"B"]; ' +
+              'Variable "$input" got invalid value ["A", null, "B"]; ' +
               'Expected non-nullable type String! not to be null at value[1].',
             locations: [{ line: 2, column: 16 }],
           },

src/execution/execute.js

@@ -1046,7 +1046,7 @@ function ensureValidRuntimeType(
     throw new GraphQLError(
       `Abstract type ${returnType.name} must resolve to an Object type at ` +
         `runtime for field ${info.parentType.name}.${info.fieldName} with ` +
-        `value "${inspect(result)}", received "${inspect(runtimeType)}". ` +
+        `value ${inspect(result)}, received "${inspect(runtimeType)}". ` +
         `Either the ${returnType.name} type should provide a "resolveType" ` +
         'function or each possible types should provide an ' +
         '"isTypeOf" function.',

src/execution/values.js

@@ -99,7 +99,7 @@ export function getVariableValues(
             coercionErrors.forEach(error => {
               error.message =
                 `Variable "$${varName}" got invalid ` +
-                `value ${JSON.stringify(value)}; ${error.message}`;
+                `value ${inspect(value)}; ${error.message}`;
             });
             errors.push(...coercionErrors);
           } else {

src/jsutils/inspect.js

@@ -7,9 +7,23 @@
  * @flow strict
  */
 
+/**
+ * Used to print values in error messages.
+ */
 export default function inspect(value: mixed): string {
-  if (Array.isArray(value)) {
-    return '[' + String(value) + ']';
-  }
-  return String(value);
+  return value && typeof value === 'object'
+    ? typeof value.inspect === 'function'
+      ? value.inspect()
+      : Array.isArray(value)
+        ? '[' + value.map(inspect).join(', ') + ']'
+        : '{' +
+          Object.keys(value)
+            .map(k => `${k}: ${inspect(value[k])}`)
+            .join(', ') +
+          '}'
+    : typeof value === 'string'
+      ? '"' + value + '"'
+      : typeof value === 'function'
+        ? `[function ${value.name}]`
+        : String(value);
 }

src/language/__tests__/parser-test.js

@@ -29,9 +29,7 @@ describe('Parser', () => {
   });
 
   it('asserts that a source to parse was provided', () => {
-    expect(() => parse({})).to.throw(
-      'Must provide Source. Received: [object Object]',
-    );
+    expect(() => parse({})).to.throw('Must provide Source. Received: {}');
   });
 
   it('parse provides useful errors', () => {

src/subscription/__tests__/subscribe-test.js

@@ -373,7 +373,7 @@ describe('Subscription Initialization Phase', () => {
 
     await expectPromiseToThrow(
       () => createSubscription(pubsub, invalidEmailSchema),
-      'Subscription field must return Async Iterable. Received: test',
+      'Subscription field must return Async Iterable. Received: "test"',
     );
   });
 
@@ -474,7 +474,7 @@ describe('Subscription Initialization Phase', () => {
         {
           message:
             'Variable "$priority" got invalid value "meow"; Expected ' +
-            'type Int; Int cannot represent non-integer value: meow',
+            'type Int; Int cannot represent non-integer value: "meow"',
           locations: [{ line: 2, column: 21 }],
         },
       ],

src/type/__tests__/definition-test.js

@@ -23,6 +23,7 @@ import {
 import { describe, it } from 'mocha';
 import { expect } from 'chai';
 
+import inspect from '../../jsutils/inspect';
 import { isObjectType, isInputType, isOutputType } from '../definition';
 
 const BlogImage = new GraphQLObjectType({
@@ -657,7 +658,7 @@ describe('Type System: Object fields must have valid resolve values', () => {
   it('rejects an empty Object field resolver', () => {
     expect(() => schemaWithObjectWithFieldResolver({})).to.throw(
       'BadResolver.badField field resolver must be a function if provided, ' +
-        'but got: [object Object].',
+        'but got: {}.',
     );
   });
 
@@ -1139,7 +1140,7 @@ describe('Type System: List must accept only types', () => {
   notTypes.forEach(type => {
     it(`rejects a non-type as item type of list: ${type}`, () => {
       expect(() => GraphQLList(type)).to.throw(
-        `Expected ${type} to be a GraphQL type.`,
+        `Expected ${inspect(type)} to be a GraphQL type.`,
       );
     });
   });
@@ -1175,7 +1176,7 @@ describe('Type System: NonNull must only accept non-nullable types', () => {
   notNullableTypes.forEach(type => {
     it(`rejects a non-type as nullable type of non-null: ${type}`, () => {
       expect(() => GraphQLNonNull(type)).to.throw(
-        `Expected ${type} to be a GraphQL nullable type.`,
+        `Expected ${inspect(type)} to be a GraphQL nullable type.`,
       );
     });
   });

src/type/__tests__/enumType-test.js

@@ -205,7 +205,7 @@ describe('Type System: Enum Values', () => {
       data: { colorEnum: null },
       errors: [
         {
-          message: 'Expected a value of type "Color" but received: GREEN',
+          message: 'Expected a value of type "Color" but received: "GREEN"',
           locations: [{ line: 1, column: 3 }],
           path: ['colorEnum'],
         },
@@ -384,7 +384,7 @@ describe('Type System: Enum Values', () => {
       errors: [
         {
           message:
-            'Expected a value of type "Complex" but received: [object Object]',
+            'Expected a value of type "Complex" but received: {someRandomValue: 123}',
           locations: [{ line: 6, column: 9 }],
           path: ['bad'],
         },

src/type/__tests__/serialization-test.js

@@ -38,7 +38,7 @@ describe('Type System: Scalar coercion', () => {
       'Int cannot represent non-integer value: -1.1',
     );
     expect(() => GraphQLInt.serialize('-1.1')).to.throw(
-      'Int cannot represent non-integer value: -1.1',
+      'Int cannot represent non-integer value: "-1.1"',
     );
     // Maybe a safe JavaScript int, but bigger than 2^32, so not
     // representable as a GraphQL Int
@@ -56,7 +56,7 @@ describe('Type System: Scalar coercion', () => {
       'Int cannot represent non 32-bit signed integer value: -1e+100',
     );
     expect(() => GraphQLInt.serialize('one')).to.throw(
-      'Int cannot represent non-integer value: one',
+      'Int cannot represent non-integer value: "one"',
     );
     // Doesn't represent number
     expect(() => GraphQLInt.serialize('')).to.throw(
@@ -92,7 +92,7 @@ describe('Type System: Scalar coercion', () => {
       'Float cannot represent non numeric value: Infinity',
     );
     expect(() => GraphQLFloat.serialize('one')).to.throw(
-      'Float cannot represent non numeric value: one',
+      'Float cannot represent non numeric value: "one"',
     );
     expect(() => GraphQLFloat.serialize('')).to.throw(
       'Float cannot represent non numeric value: (empty string)',

src/type/__tests__/validation-test.js

@@ -383,7 +383,7 @@ describe('Type System: A Schema must have Object root types', () => {
     });
     expect(validateSchema(schema)).to.deep.equal([
       {
-        message: 'Expected directive but got: somedirective.',
+        message: 'Expected directive but got: "somedirective".',
       },
     ]);
   });
@@ -861,10 +861,10 @@ describe('Type System: Object fields must have output types', () => {
     const schema = schemaWithObjectFieldOfType(Number);
     expect(validateSchema(schema)).to.deep.equal([
       {
-        message: `The type of BadObject.badField must be Output Type but got: ${Number}.`,
+        message: `The type of BadObject.badField must be Output Type but got: [function Number].`,
       },
       {
-        message: `Expected GraphQL named type but got: ${Number}.`,
+        message: `Expected GraphQL named type but got: [function Number].`,
       },
     ]);
   });
@@ -1162,13 +1162,13 @@ describe('Type System: Interface fields must have output types', () => {
     const schema = schemaWithInterfaceFieldOfType(Number);
     expect(validateSchema(schema)).to.deep.equal([
       {
-        message: `The type of BadInterface.badField must be Output Type but got: ${Number}.`,
+        message: `The type of BadInterface.badField must be Output Type but got: [function Number].`,
       },
       {
-        message: `Expected GraphQL named type but got: ${Number}.`,
+        message: `Expected GraphQL named type but got: [function Number].`,
       },
       {
-        message: `The type of BadImplementing.badField must be Output Type but got: ${Number}.`,
+        message: `The type of BadImplementing.badField must be Output Type but got: [function Number].`,
       },
     ]);
   });
@@ -1275,10 +1275,10 @@ describe('Type System: Field arguments must have input types', () => {
     const schema = schemaWithArgOfType(Number);
     expect(validateSchema(schema)).to.deep.equal([
       {
-        message: `The type of BadObject.badField(badArg:) must be Input Type but got: ${Number}.`,
+        message: `The type of BadObject.badField(badArg:) must be Input Type but got: [function Number].`,
       },
       {
-        message: `Expected GraphQL named type but got: ${Number}.`,
+        message: `Expected GraphQL named type but got: [function Number].`,
       },
     ]);
   });
@@ -1359,10 +1359,10 @@ describe('Type System: Input Object fields must have input types', () => {
     const schema = schemaWithInputFieldOfType(Number);
     expect(validateSchema(schema)).to.deep.equal([
       {
-        message: `The type of BadInputObject.badField must be Input Type but got: ${Number}.`,
+        message: `The type of BadInputObject.badField must be Input Type but got: [function Number].`,
       },
       {
-        message: `Expected GraphQL named type but got: ${Number}.`,
+        message: `Expected GraphQL named type but got: [function Number].`,
       },
     ]);
   });

src/utilities/__tests__/coerceValue-test.js

@@ -35,7 +35,7 @@ describe('coerceValue', () => {
       it('returns error for array input as string', () => {
         const result = coerceValue([1, 2, 3], scalar);
         expectErrors(result).to.deep.equal([
-          `Expected type ${scalar}; String cannot represent an array value: [1,2,3]`,
+          `Expected type ${scalar}; String cannot represent an array value: [1, 2, 3]`,
         ]);
       });
     });
@@ -79,7 +79,7 @@ describe('coerceValue', () => {
     it('returns a single error for float input as int', () => {
       const result = coerceValue('1.5', GraphQLInt);
       expectErrors(result).to.deep.equal([
-        'Expected type Int; Int cannot represent non-integer value: 1.5',
+        'Expected type Int; Int cannot represent non-integer value: "1.5"',
       ]);
     });
 
@@ -100,14 +100,14 @@ describe('coerceValue', () => {
     it('returns a single error for char input', () => {
       const result = coerceValue('a', GraphQLInt);
       expectErrors(result).to.deep.equal([
-        'Expected type Int; Int cannot represent non-integer value: a',
+        'Expected type Int; Int cannot represent non-integer value: "a"',
       ]);
     });
 
     it('returns a single error for char input', () => {
       const result = coerceValue('meow', GraphQLInt);
       expectErrors(result).to.deep.equal([
-        'Expected type Int; Int cannot represent non-integer value: meow',
+        'Expected type Int; Int cannot represent non-integer value: "meow"',
       ]);
     });
   });
@@ -157,14 +157,14 @@ describe('coerceValue', () => {
     it('returns a single error for char input', () => {
       const result = coerceValue('a', GraphQLFloat);
       expectErrors(result).to.deep.equal([
-        'Expected type Float; Float cannot represent non numeric value: a',
+        'Expected type Float; Float cannot represent non numeric value: "a"',
       ]);
     });
 
     it('returns a single error for char input', () => {
       const result = coerceValue('meow', GraphQLFloat);
       expectErrors(result).to.deep.equal([
-        'Expected type Float; Float cannot represent non numeric value: meow',
+        'Expected type Float; Float cannot represent non numeric value: "meow"',
       ]);
     });
   });
@@ -226,15 +226,15 @@ describe('coerceValue', () => {
     it('returns no error for an invalid field', () => {
       const result = coerceValue({ foo: 'abc' }, TestInputObject);
       expectErrors(result).to.deep.equal([
-        'Expected type Int at value.foo; Int cannot represent non-integer value: abc',
+        'Expected type Int at value.foo; Int cannot represent non-integer value: "abc"',
       ]);
     });
 
     it('returns multiple errors for multiple invalid fields', () => {
       const result = coerceValue({ foo: 'abc', bar: 'def' }, TestInputObject);
       expectErrors(result).to.deep.equal([
-        'Expected type Int at value.foo; Int cannot represent non-integer value: abc',
-        'Expected type Int at value.bar; Int cannot represent non-integer value: def',
+        'Expected type Int at value.foo; Int cannot represent non-integer value: "abc"',
+        'Expected type Int at value.bar; Int cannot represent non-integer value: "def"',
       ]);
     });