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diff --git a/node_modules/webpack/lib/util/MapHelpers.js b/node_modules/webpack/lib/util/MapHelpers.js
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+/*
+	MIT License http://www.opensource.org/licenses/mit-license.php
+	Author Tobias Koppers @sokra
+*/
+
+"use strict";
+
+/**
+ * getOrInsert is a helper function for maps that allows you to get a value
+ * from a map if it exists, or insert a new value if it doesn't. If it value doesn't
+ * exist, it will be computed by the provided function.
+ * @template K
+ * @template V
+ * @param {Map<K, V>} map The map object to check
+ * @param {K} key The key to check
+ * @param {function(): V} computer function which will compute the value if it doesn't exist
+ * @returns {V} The value from the map, or the computed value
+ * @example
+ * ```js
+ * const map = new Map();
+ * const value = getOrInsert(map, "key", () => "value");
+ * console.log(value); // "value"
+ * ```
+ */
+module.exports.getOrInsert = (map, key, computer) => {
+	// Grab key from map
+	const value = map.get(key);
+	// If the value already exists, return it
+	if (value !== undefined) return value;
+	// Otherwise compute the value, set it in the map, and return it
+	const newValue = computer();
+	map.set(key, newValue);
+	return newValue;
+};