inspect: Limit maximum number of printed items to 10

IvanGoncharov · IvanGoncharov · commit b3d9a5cf358b · 2019-03-15T16:52:43.000+02:00
diff --git a/src/jsutils/__tests__/inspect-test.js b/src/jsutils/__tests__/inspect-test.js
@@ -54,6 +54,18 @@ describe('inspect', () => {
     expect(inspect([null])).to.equal('[null]');
     expect(inspect([1, NaN])).to.equal('[1, NaN]');
     expect(inspect([['a', 'b'], 'c'])).to.equal('[["a", "b"], "c"]');
+
+    expect(inspect([0, 1, 2, 3, 4, 5, 6, 7, 8, 9])).to.equal(
+      '[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]',
+    );
+
+    expect(inspect([0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10])).to.equal(
+      '[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, ... 1 more item]',
+    );
+
+    expect(inspect([0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11])).to.equal(
+      '[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, ... 2 more items]',
+    );
   });
 
   it('object', () => {
diff --git a/src/jsutils/inspect.js b/src/jsutils/inspect.js
@@ -9,6 +9,8 @@
 
 import nodejsCustomInspectSymbol from './nodejsCustomInspectSymbol';
 
+const MAX_ARRAY_LENGTH = 10;
+
 /**
  * Used to print values in error messages.
  */
@@ -29,7 +31,7 @@ export default function inspect(value: mixed): string {
             ? customValue
             : inspect(customValue);
         } else if (Array.isArray(value)) {
-          return '[' + value.map(inspect).join(', ') + ']';
+          return inspectArray(value);
         }
 
         const properties = Object.keys(value)
@@ -43,6 +45,24 @@ export default function inspect(value: mixed): string {
   }
 }
 
+function inspectArray(array) {
+  const len = Math.min(MAX_ARRAY_LENGTH, array.length);
+  const remaining = array.length - len;
+  const items = [];
+
+  for (let i = 0; i < len; ++i) {
+    items.push(inspect(array[i]));
+  }
+
+  if (remaining === 1) {
+    items.push('... 1 more item');
+  } else if (remaining > 1) {
+    items.push(`... ${remaining} more items`);
+  }
+
+  return '[' + items.join(', ') + ']';
+}
+
 function getCustomFn(object) {
   const customInspectFn = object[String(nodejsCustomInspectSymbol)];
 
