flow like the river

BACK_BACK/node_modules/graphql/jsutils/memoize3.js.flow

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+// @flow strict
+/**
+ * Memoizes the provided three-argument function.
+ */
+export default function memoize3<
+  A1: { ... } | $ReadOnlyArray<mixed>,
+  A2: { ... } | $ReadOnlyArray<mixed>,
+  A3: { ... } | $ReadOnlyArray<mixed>,
+  R: mixed,
+>(fn: (A1, A2, A3) => R): (A1, A2, A3) => R {
+  let cache0;
+
+  return function memoized(a1, a2, a3) {
+    if (!cache0) {
+      cache0 = new WeakMap();
+    }
+    let cache1 = cache0.get(a1);
+    let cache2;
+    if (cache1) {
+      cache2 = cache1.get(a2);
+      if (cache2) {
+        const cachedValue = cache2.get(a3);
+        if (cachedValue !== undefined) {
+          return cachedValue;
+        }
+      }
+    } else {
+      cache1 = new WeakMap();
+      cache0.set(a1, cache1);
+    }
+    if (!cache2) {
+      cache2 = new WeakMap();
+      cache1.set(a2, cache2);
+    }
+    const newValue = fn(a1, a2, a3);
+    cache2.set(a3, newValue);
+    return newValue;
+  };
+}