util,assert: expose util.isDeepStrictEqual()

Provide `util.isDeepStrictEqual()` that works like `assert.deepStrictEqual()` but returns a boolean rather than throwing an error. Several userland modules have needed this functionality and implemented it independently. This functionality already exists in Node.js core, so this exposes it for use by modules. Modules that have needed this functionality include `lodash`, `concordance` (used by `ava`), and `qunit`. PR-URL: nodejs#16084 Reviewed-By: James M Snell <[email protected]> Reviewed-By: Evan Lucas <[email protected]> Reviewed-By: Joyee Cheung <[email protected]> Reviewed-By: Refael Ackermann <[email protected]> Reviewed-By: Colin Ihrig <[email protected]> Reviewed-By: Michaël Zasso <[email protected]> Reviewed-By: Jeremiah Senkpiel <[email protected]> Reviewed-By: Ali Ijaz Sheikh <[email protected]> Reviewed-By: Ruben Bridgewater <[email protected]>
Trott · Oct 26, 2017 · 3673208 · 3673208
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diff --git a/doc/api/assert.md b/doc/api/assert.md
@@ -134,7 +134,7 @@ changes:
 * `expected` {any}
 * `message` {any}
 
-Similar to `assert.deepEqual()` with the following exceptions:
+Identical to [`assert.deepEqual()`][] with the following exceptions:
 
 1. Primitive values besides `NaN` are compared using the [Strict Equality
    Comparison][] ( `===` ). Set and Map values, Map keys and `NaN` are compared

diff --git a/doc/api/util.md b/doc/api/util.md
@@ -455,6 +455,21 @@ util.inspect.defaultOptions.maxArrayLength = null;
 console.log(arr); // logs the full array
 ```
 
+## util.isDeepStrictEqual(val1, val2)
+<!-- YAML
+added: REPLACEME
+-->
+
+* `val1` {any}
+* `val2` {any}
+* Returns: {string}
+
+Returns `true` if there is deep strict equality between `val` and `val2`.
+Otherwise, returns `false`.
+
+See [`assert.deepStrictEqual()`][] for more information about deep strict
+equality.
+
 ## util.promisify(original)
 <!-- YAML
 added: v8.0.0
@@ -1187,6 +1202,7 @@ Deprecated predecessor of `console.log`.
 [`Buffer.isBuffer()`]: buffer.html#buffer_class_method_buffer_isbuffer_obj
 [`Error`]: errors.html#errors_class_error
 [`Object.assign()`]: https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/Object/assign
+[`assert.deepStrictEqual()`]: assert.html#assert_assert_deepstrictequal_actual_expected_message
 [`console.error()`]: console.html#console_console_error_data_args
 [`console.log()`]: console.html#console_console_log_data_args
 [`util.inspect()`]: #util_util_inspect_object_options