From: Doug Brunner <doug.a.brunner@gmail.com>
Date: Thu, 16 Dec 2021 12:34:30 +0000 (-0800)
Subject: Docs/clarify usage of ticks callback (#9991) (#9994)
X-Git-Tag: v3.7.0~7
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=977a4b8d85f21ed885f24e50c8fb6ddf5495fda1;p=thirdparty%2FChart.js.git

Docs/clarify usage of ticks callback (#9991) (#9994)

* Docs/clarify usage of ticks callback (#9991)

* Docs/Fixed inconsistent variable names (#9991)

Co-authored-by: Doug Brunner <doug@epicycloidengr.com>
---

diff --git a/docs/axes/labelling.md b/docs/axes/labelling.md
index 83c365807..9ab75ffab 100644
--- a/docs/axes/labelling.md
+++ b/docs/axes/labelling.md
@@ -45,7 +45,7 @@ const chart = new Chart(ctx, {
             y: {
                 ticks: {
                     // Include a dollar sign in the ticks
-                    callback: function(value, index, values) {
+                    callback: function(value, index, ticks) {
                         return '$' + value;
                     }
                 }
@@ -55,6 +55,13 @@ const chart = new Chart(ctx, {
 });
 ```
 
+Keep in mind that overriding `ticks.callback` means that you are responsible for all formatting of the label. Depending on your use case, you may want to call the default formatter and then modify its output. In the example above, that would look like:
+
+```javascript
+                        // call the default formatter, forwarding `this`
+                        return '$' + Chart.Ticks.formatters.numeric.apply(this, [value, index, ticks]);
+```
+
 Related samples:
 
 * [Tick configuration sample](../samples/scale-options/ticks)