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node_modules/fast-equals/recipes/legacy-regexp-support.md

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+# Legacy environment support for `RegExp` comparators
+
+Starting in `4.x.x`, `RegExp.prototype.flags` is expected to be available in the environment. All modern browsers support this feature, however there may be situations where a legacy environmental support is required (example: IE11). If you need to support such an environment and polyfilling is not an option, creating a custom comparator that uses a more verbose comparison of all possible flags is a simple solution.
+
+```ts
+import { createCustomEqual, sameValueZeroEqual } from 'deep-Equals';
+
+const areRegExpsEqual = (a: RegExp, b: RegExp) =>
+  a.source === b.source &&
+  a.global === b.global &&
+  a.ignoreCase === b.ignoreCase &&
+  a.multiline === b.multiline &&
+  a.unicode === b.unicode &&
+  a.sticky === b.sticky &&
+  a.lastIndex === b.lastIndex;
+
+const deepEqual = createCustomEqual({
+  createCustomConfig: () => ({ areRegExpsEqual }),
+});
+const shallowEqual = createCustomEqual({
+  comparator: sameValueZero,
+  createCustomConfig: () => ({ areRegExpsEqual }),
+});
+```