Bump to v3.0.0.

collection/indexBy.js

@@ -0,0 +1,46 @@
+import createAggregator from '../internal/createAggregator';
+
+/**
+ * Creates an object composed of keys generated from the results of running
+ * each element of `collection` through `iteratee`. The corresponding value
+ * of each key is the last element responsible for generating the key. The
+ * iteratee function is bound to `thisArg` and invoked with three arguments;
+ * (value, index|key, collection).
+ *
+ * If a property name is provided for `predicate` the created "_.property"
+ * style callback returns the property value of the given element.
+ *
+ * If an object is provided for `predicate` the created "_.matches" style
+ * callback returns `true` for elements that have the properties of the given
+ * object, else `false`.
+ *
+ * @static
+ * @memberOf _
+ * @category Collection
+ * @param {Array|Object|string} collection The collection to iterate over.
+ * @param {Function|Object|string} [iteratee=_.identity] The function invoked
+ *  per iteration. If a property name or object is provided it is used to
+ *  create a "_.property" or "_.matches" style callback respectively.
+ * @param {*} [thisArg] The `this` binding of `iteratee`.
+ * @returns {Object} Returns the composed aggregate object.
+ * @example
+ *
+ * var keyData = [
+ *   { 'dir': 'left', 'code': 97 },
+ *   { 'dir': 'right', 'code': 100 }
+ * ];
+ *
+ * _.indexBy(keyData, 'dir');
+ * // => { 'left': { 'dir': 'left', 'code': 97 }, 'right': { 'dir': 'right', 'code': 100 } }
+ *
+ * _.indexBy(keyData, function(object) { return String.fromCharCode(object.code); });
+ * // => { 'a': { 'dir': 'left', 'code': 97 }, 'd': { 'dir': 'right', 'code': 100 } }
+ *
+ * _.indexBy(keyData, function(object) { return this.fromCharCode(object.code); }, String);
+ * // => { 'a': { 'dir': 'left', 'code': 97 }, 'd': { 'dir': 'right', 'code': 100 } }
+ */
+var indexBy = createAggregator(function(result, value, key) {
+  result[key] = value;
+});
+
+export default indexBy;