diff --git a/lib/assert.js b/lib/assert.js
index 180744c9c0c..2164c22958d 100644
--- a/lib/assert.js
+++ b/lib/assert.js
@@ -54,9 +54,6 @@ const meta = [
 
 const escapeFn = (str) => meta[str.charCodeAt(0)];
 
-const ERR_DIFF_NOT_EQUAL = 1;
-const ERR_DIFF_EQUAL = 2;
-
 let warned = false;
 
 // The assert module provides functions that throw
@@ -321,8 +318,7 @@ assert.deepStrictEqual = function deepStrictEqual(actual, expected, message) {
       expected,
       message,
       operator: 'deepStrictEqual',
-      stackStartFn: deepStrictEqual,
-      errorDiff: ERR_DIFF_EQUAL
+      stackStartFn: deepStrictEqual
     });
   }
 };
@@ -335,8 +331,7 @@ function notDeepStrictEqual(actual, expected, message) {
       expected,
       message,
       operator: 'notDeepStrictEqual',
-      stackStartFn: notDeepStrictEqual,
-      errorDiff: ERR_DIFF_NOT_EQUAL
+      stackStartFn: notDeepStrictEqual
     });
   }
 }
@@ -348,8 +343,7 @@ assert.strictEqual = function strictEqual(actual, expected, message) {
       expected,
       message,
       operator: 'strictEqual',
-      stackStartFn: strictEqual,
-      errorDiff: ERR_DIFF_EQUAL
+      stackStartFn: strictEqual
     });
   }
 };
@@ -361,8 +355,7 @@ assert.notStrictEqual = function notStrictEqual(actual, expected, message) {
       expected,
       message,
       operator: 'notStrictEqual',
-      stackStartFn: notStrictEqual,
-      errorDiff: ERR_DIFF_NOT_EQUAL
+      stackStartFn: notStrictEqual
     });
   }
 };
@@ -389,8 +382,7 @@ function compareExceptionKey(actual, expected, key, message, keys) {
         actual: a,
         expected: b,
         operator: 'deepStrictEqual',
-        stackStartFn: assert.throws,
-        errorDiff: ERR_DIFF_EQUAL
+        stackStartFn: assert.throws
       });
       Error.stackTraceLimit = tmpLimit;
       message = err.message;
diff --git a/lib/internal/errors.js b/lib/internal/errors.js
index 22d10068283..eff720f0905 100644
--- a/lib/internal/errors.js
+++ b/lib/internal/errors.js
@@ -395,8 +395,7 @@ class AssertionError extends Error {
       expected,
       message,
       operator,
-      stackStartFn,
-      errorDiff = 0
+      stackStartFn
     } = options;
 
     if (message != null) {
@@ -427,15 +426,10 @@ class AssertionError extends Error {
         expected = copyError(expected);
       }
 
-      if (errorDiff === 0) {
-        let res = util.inspect(actual);
-        let other = util.inspect(expected);
-        if (res.length > 128)
-          res = `${res.slice(0, 125)}...`;
-        if (other.length > 128)
-          other = `${other.slice(0, 125)}...`;
-        super(`${res} ${operator} ${other}`);
-      } else if (errorDiff === 1) {
+      if (operator === 'deepStrictEqual' || operator === 'strictEqual') {
+        super(createErrDiff(actual, expected, operator));
+      } else if (operator === 'notDeepStrictEqual' ||
+        operator === 'notStrictEqual') {
         // In case the objects are equal but the operator requires unequal, show
         // the first object and say A equals B
         const res = inspectValue(actual);
@@ -457,7 +451,13 @@ class AssertionError extends Error {
           super(`${base}\n\n  ${res.join('\n  ')}\n`);
         }
       } else {
-        super(createErrDiff(actual, expected, operator));
+        let res = util.inspect(actual);
+        let other = util.inspect(expected);
+        if (res.length > 128)
+          res = `${res.slice(0, 125)}...`;
+        if (other.length > 128)
+          other = `${other.slice(0, 125)}...`;
+        super(`${res} ${operator} ${other}`);
       }
     }