Merge pull request #12686 from Automattic/vkarpov15/gh-12599

docs: fix inverted explanation of `justOne` option for populate

Author: hasezoey

lib/model.js

@@ -4556,7 +4556,7 @@ Model.validate = function validate(obj, pathsToValidate, context, callback) {
  * - match: optional query conditions to match
  * - model: optional name of the model to use for population
  * - options: optional query options like sort, limit, etc
- * - justOne: optional boolean, if true Mongoose will always set `path` to an array. Inferred from schema by default.
+ * - justOne: optional boolean, if true Mongoose will always set `path` to a document, or `null` if no document was found. If false, Mongoose will always set `path` to an array, which will be empty if no documents are found. Inferred from schema by default.
  * - strictPopulate: optional boolean, set to `false` to allow populating paths that aren't in the schema.
  *
  * #### Example:

types/populate.d.ts

@@ -26,8 +26,9 @@ declare module 'mongoose' {
      /** deep populate */
      populate?: string | PopulateOptions | (string | PopulateOptions)[];
      /**
-     * If true Mongoose will always set `path` to an array, if false Mongoose will
-     * always set `path` to a document. Inferred from schema by default.
+     * If true Mongoose will always set `path` to a document, or `null` if no document was found.
+     * If false Mongoose will always set `path` to an array, which will be empty if no documents are found.
+     * Inferred from schema by default.
      */
      justOne?: boolean;
      /** transform function to call on every populated doc */