diff --git a/src/postgrest.js b/src/postgrest.js
index 9ce8460..21538a5 100644
--- a/src/postgrest.js
+++ b/src/postgrest.js
@@ -174,6 +174,11 @@ export default (api_root, auth={}) => {
 							if (typeof v == 'undefined' || (!v && v !== 0))
 								return undefined
 
+							// generate value if v is a function
+							if (typeof v == 'function')
+								v = v()
+
+							// format v on k & op
 							if (op == 'like')
 								v = `*${v}*`
 							else if (op == 'like.right') {