Document that meanBy can return NaN if array is empty.
#6045
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ljharb
approved these changes
Nov 11, 2025
UlisesGascon
approved these changes
Nov 11, 2025
jonchurch
requested changes
Dec 2, 2025
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The documentation is currently generated based on waht is in the JSDoc of the source. Then copied over to the lodash.com repo and deployed.
You will need to make this change in the source's JSDoc to ensure it persists through the next website deploy.
Consider adding an example as well.
diff --git a/lodash.js b/lodash.js
index 1d232ac5e..26fc1939f 100644
--- a/lodash.js
+++ b/lodash.js
@@ -16437,7 +16437,7 @@
* @category Math
* @param {Array} array The array to iterate over.
* @param {Function} [iteratee=_.identity] The iteratee invoked per element.
- * @returns {number} Returns the mean.
+ * @returns {number} Returns the mean. If array is empty, then will return `NaN`
* @example
*
* var objects = [{ 'n': 4 }, { 'n': 2 }, { 'n': 8 }, { 'n': 6 }];
@@ -16448,6 +16448,10 @@
* // The `_.property` iteratee shorthand.
* _.meanBy(objects, 'n');
* // => 5
+ *
+ * // If array is empty, then will return NaN
+ * _.meanBy([], 'foo')
+ * // => NaN
*/
function meanBy(array, iteratee) {
return baseMean(array, getIteratee(iteratee, 2));
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Merging this fixes #5901 by documenting this behavior.