From f8a5ad3569f84d3777155404dd44025e49e8541d Mon Sep 17 00:00:00 2001
From: Phil Burrows <github@philburrows.com>
Date: Thu, 30 Apr 2020 10:35:02 -0500
Subject: [PATCH] implement requested changes from PR feedback

---
 cypress/types/plugin.spec.ts | 13 ++++++++++++-
 index.d.ts                   |  9 +++++++--
 src/index.js                 |  5 ++++-
 3 files changed, 23 insertions(+), 4 deletions(-)

diff --git a/cypress/types/plugin.spec.ts b/cypress/types/plugin.spec.ts
index 4b27808..eb49850 100644
--- a/cypress/types/plugin.spec.ts
+++ b/cypress/types/plugin.spec.ts
@@ -18,7 +18,18 @@ cy.waitUntil(() => Promise.resolve(false), { timeout: 500 });
 cy.waitUntil(() => true, { errorMsg: "Custom error message" });
 cy.waitUntil(() => false, { errorMsg: "Custom error message" });
 cy.waitUntil(() => Promise.resolve(true), { errorMsg: "Custom error message" });
-cy.waitUntil(() => Promise.resolve(false), { errorMsg: "Custom error message" });
+cy.waitUntil(() => Promise.resolve(false), {
+  errorMsg: "Custom error message",
+});
+
+cy.waitUntil(() => true, { errorMsg: () => "Custom error message" });
+cy.waitUntil(() => false, { errorMsg: () => "Custom error message" });
+cy.waitUntil(() => Promise.resolve(true), {
+  errorMsg: () => "Custom error message",
+});
+cy.waitUntil(() => Promise.resolve(false), {
+  errorMsg: () => "Custom error message",
+});
 
 cy.waitUntil(() => true, { description: "Custom description" });
 
diff --git a/index.d.ts b/index.d.ts
index 548e939..5f67523 100644
--- a/index.d.ts
+++ b/index.d.ts
@@ -1,11 +1,16 @@
 /// <reference types="Cypress" />
 
-type WaitUntilLog = Pick<Cypress.LogConfig, "name" | "message" | "consoleProps">;
+type WaitUntilLog = Pick<
+  Cypress.LogConfig,
+  "name" | "message" | "consoleProps"
+>;
+
+type ErrorMsgCallback = (result: any, options: any) => string;
 
 interface WaitUntilOptions {
   timeout?: number;
   interval?: number;
-  errorMsg?: string;
+  errorMsg?: string | ErrorMsgCallback;
   description?: string;
   customMessage?: string;
   verbose?: boolean;
diff --git a/src/index.js b/src/index.js
index 21ff917..201de48 100644
--- a/src/index.js
+++ b/src/index.js
@@ -57,7 +57,10 @@ const waitUntil = (subject, checkFunction, originalOptions = {}) => {
       return result;
     }
     if (retries < 1) {
-      const msg = options.errorMsg.call ? options.errorMsg() : options.errorMsg;
+      const msg =
+        options.errorMsg instanceof Function
+          ? options.errorMsg({ result, options })
+          : options.errorMsg;
       throw new Error(msg);
     }
     cy.wait(options.interval, { log: false }).then(() => {