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diff --git a/popperjs/package/lib/utils/computeAutoPlacement.js.flow b/popperjs/package/lib/utils/computeAutoPlacement.js.flow
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+// @flow
+import type { State, Padding } from '../types';
+import type {
+  Placement,
+  ComputedPlacement,
+  Boundary,
+  RootBoundary,
+} from '../enums';
+import getVariation from './getVariation';
+import {
+  variationPlacements,
+  basePlacements,
+  placements as allPlacements,
+} from '../enums';
+import detectOverflow from './detectOverflow';
+import getBasePlacement from './getBasePlacement';
+
+type Options = {
+  placement: Placement,
+  padding: Padding,
+  boundary: Boundary,
+  rootBoundary: RootBoundary,
+  flipVariations: boolean,
+  allowedAutoPlacements?: Array<Placement>,
+};
+
+type OverflowsMap = { [ComputedPlacement]: number };
+
+export default function computeAutoPlacement(
+  state: $Shape<State>,
+  options: Options = {}
+): Array<ComputedPlacement> {
+  const {
+    placement,
+    boundary,
+    rootBoundary,
+    padding,
+    flipVariations,
+    allowedAutoPlacements = allPlacements,
+  } = options;
+
+  const variation = getVariation(placement);
+
+  const placements = variation
+    ? flipVariations
+      ? variationPlacements
+      : variationPlacements.filter(
+          (placement) => getVariation(placement) === variation
+        )
+    : basePlacements;
+
+  let allowedPlacements = placements.filter(
+    (placement) => allowedAutoPlacements.indexOf(placement) >= 0
+  );
+
+  if (allowedPlacements.length === 0) {
+    allowedPlacements = placements;
+
+    if (false) {
+      console.error(
+        [
+          'Popper: The `allowedAutoPlacements` option did not allow any',
+          'placements. Ensure the `placement` option matches the variation',
+          'of the allowed placements.',
+          'For example, "auto" cannot be used to allow "bottom-start".',
+          'Use "auto-start" instead.',
+        ].join(' ')
+      );
+    }
+  }
+
+  // $FlowFixMe[incompatible-type]: Flow seems to have problems with two array unions...
+  const overflows: OverflowsMap = allowedPlacements.reduce((acc, placement) => {
+    acc[placement] = detectOverflow(state, {
+      placement,
+      boundary,
+      rootBoundary,
+      padding,
+    })[getBasePlacement(placement)];
+
+    return acc;
+  }, {});
+
+  return Object.keys(overflows).sort((a, b) => overflows[a] - overflows[b]);
+}