Index: frontend/node_modules/lodash/differenceBy.js
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--- frontend/node_modules/lodash/differenceBy.js	(revision 9af201e94b5a79beb92a30858fc54de4bc3b9449)
+++ frontend/node_modules/lodash/differenceBy.js	(revision 9af201e94b5a79beb92a30858fc54de4bc3b9449)
@@ -0,0 +1,44 @@
+var baseDifference = require('./_baseDifference'),
+    baseFlatten = require('./_baseFlatten'),
+    baseIteratee = require('./_baseIteratee'),
+    baseRest = require('./_baseRest'),
+    isArrayLikeObject = require('./isArrayLikeObject'),
+    last = require('./last');
+
+/**
+ * This method is like `_.difference` except that it accepts `iteratee` which
+ * is invoked for each element of `array` and `values` to generate the criterion
+ * by which they're compared. The order and references of result values are
+ * determined by the first array. The iteratee is invoked with one argument:
+ * (value).
+ *
+ * **Note:** Unlike `_.pullAllBy`, this method returns a new array.
+ *
+ * @static
+ * @memberOf _
+ * @since 4.0.0
+ * @category Array
+ * @param {Array} array The array to inspect.
+ * @param {...Array} [values] The values to exclude.
+ * @param {Function} [iteratee=_.identity] The iteratee invoked per element.
+ * @returns {Array} Returns the new array of filtered values.
+ * @example
+ *
+ * _.differenceBy([2.1, 1.2], [2.3, 3.4], Math.floor);
+ * // => [1.2]
+ *
+ * // The `_.property` iteratee shorthand.
+ * _.differenceBy([{ 'x': 2 }, { 'x': 1 }], [{ 'x': 1 }], 'x');
+ * // => [{ 'x': 2 }]
+ */
+var differenceBy = baseRest(function(array, values) {
+  var iteratee = last(values);
+  if (isArrayLikeObject(iteratee)) {
+    iteratee = undefined;
+  }
+  return isArrayLikeObject(array)
+    ? baseDifference(array, baseFlatten(values, 1, isArrayLikeObject, true), baseIteratee(iteratee, 2))
+    : [];
+});
+
+module.exports = differenceBy;