diff --git a/README.md b/README.md
index 7b6fa91ec..79fd2a21a 100644
--- a/README.md
+++ b/README.md
@@ -428,8 +428,8 @@ const rgbToHex = (r, g, b) => ((r << 16) + (g << 8) + b).toString(16).padStart(6
 Run an array of promises in series using `Array.reduce()` by creating a promise chain, where each promise returns the next promise when resolved.
 
 ```js
-var series = ps => ps.reduce((p, next) => p.then(next), Promise.resolve());
-// var delay = (d) => new Promise(r => setTimeout(r, d))
+const series = ps => ps.reduce((p, next) => p.then(next), Promise.resolve());
+// const delay = (d) => new Promise(r => setTimeout(r, d))
 // series([() => delay(1000), () => delay(2000)]) -> executes each promise sequentially, taking a total of 3 seconds to complete
 ```
 
diff --git a/snippets/run-promises-in-series.md b/snippets/run-promises-in-series.md
index b22d9e00f..2193e8df4 100644
--- a/snippets/run-promises-in-series.md
+++ b/snippets/run-promises-in-series.md
@@ -3,7 +3,7 @@
 Run an array of promises in series using `Array.reduce()` by creating a promise chain, where each promise returns the next promise when resolved.
 
 ```js
-var series = ps => ps.reduce((p, next) => p.then(next), Promise.resolve());
-// var delay = (d) => new Promise(r => setTimeout(r, d))
+const series = ps => ps.reduce((p, next) => p.then(next), Promise.resolve());
+// const delay = (d) => new Promise(r => setTimeout(r, d))
 // series([() => delay(1000), () => delay(2000)]) -> executes each promise sequentially, taking a total of 3 seconds to complete
 ```