Add ArgumentError.checkNotNull utility

In the places where other utilities like `RangeError.checkNotNegative` are used it reads nicer to call through a similar signature than to follow a conditional with the utility. Change-Id: Idd89b2934020fb55e57a22c39773fd7879d1c28f Reviewed-on: https://dart-review.googlesource.com/c/81287 Commit-Queue: Nate Bosch <[email protected]> Reviewed-by: Lasse R.H. Nielsen <[email protected]>
flutter · Oct 24, 2018 · 655310d · 655310d
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -151,6 +151,7 @@ a InstanceTypeError if the instance isn't of the class expected
 ### Core library changes
 
 *   Add `HashMap.fromEntries` and `LinkedHashmap.fromEntries` constructors.
+*   Add `ArgumentError.checkNotNull` utility method.
 
 ### Dart VM
 

diff --git a/sdk/lib/core/errors.dart b/sdk/lib/core/errors.dart
@@ -173,6 +173,13 @@ class ArgumentError extends Error {
         message = "Must not be null",
         invalidValue = null;
 
+  /**
+   * Throws if [argument] is `null`.
+   */
+  static void checkNotNull(Object argument, [String name]) {
+    if (argument == null) throw ArgumentError.notNull(name);
+  }
+
   // Helper functions for toString overridden in subclasses.
   String get _errorName => "Invalid argument${!_hasValue ? "(s)" : ""}";
   String get _errorExplanation => "";