docs(schema): add examples for remaining functions

lib/schema.js

@@ -267,6 +267,13 @@ Schema.prototype.tree;
 /**
  * Returns a deep copy of the schema
  *
+ * ####Example:
+ *
+ *     const schema = new Schema({ name: String });
+ *     const clone = schema.clone();
+ *     clone === schema; // false
+ *     clone.path('name'); // SchemaString { ... }
+ *
  * @return {Schema} the cloned schema
  * @api public
  * @memberOf Schema
@@ -763,7 +770,17 @@ Schema.prototype.interpretAsType = function(path, obj, options) {
 /**
  * Iterates the schemas paths similar to Array#forEach.
  *
- * The callback is passed the pathname and schemaType as arguments on each iteration.
+ * The callback is passed the pathname and the schemaType instance.
+ *
+ * ####Example:
+ *
+ *     const userSchema = new Schema({ name: String, registeredAt: Date });
+ *     userSchema.eachPath((pathname, schematype) => {
+ *       // Prints twice:
+ *       // name SchemaString { ... }
+ *       // registeredAt SchemaDate { ... }
+ *       console.log(pathname, schematype);
+ *     });
  *
  * @param {Function} fn callback function
  * @return {Schema} this
@@ -1389,8 +1406,15 @@ const setSafe = util.deprecate(function setSafe(options, value) {
 /**
  * Gets a schema option.
  *
+ * ####Example:
+ *
+ *     schema.get('strict'); // true
+ *     schema.set('strict', false);
+ *     schema.get('strict'); // false
+ *
  * @param {String} key option name
  * @api public
+ * @return {Any} the option's value
  */
 
 Schema.prototype.get = function(key) {
@@ -1420,7 +1444,19 @@ Object.defineProperty(Schema, 'indexTypes', {
  * Returns a list of indexes that this schema declares, via `schema.index()`
  * or by `index: true` in a path's options.
  *
+ * ####Example:
+ *
+ *     const userSchema = new Schema({
+ *       email: { type: String, required: true, unique: true },
+ *       registeredAt: { type: Date, index: true }
+ *     });
+ *
+ *     // [ [ { email: 1 }, { unique: true, background: true } ],
+ *     //   [ { registeredAt: 1 }, { background: true } ] ]
+ *     userSchema.indexes();
+ *
  * @api public
+ * @return {Array} list of indexes defined in the schema
  */
 
 Schema.prototype.indexes = function() {