Make "m" the default size of EuiButton

CHANGELOG.md

@@ -1,6 +1,6 @@
 ## [`master`](https://github.com/elastic/eui/tree/master)
 
-No public interface changes since `9.4.2`.
+- Changed `EuiButton` to use "m" as it's default `size` prop ([#1742](https://github.com/elastic/eui/pull/1742))
 
 ## [`9.4.2`](https://github.com/elastic/eui/tree/v9.4.2)
 

src/components/button/__snapshots__/button.test.js.snap

@@ -331,6 +331,21 @@ exports[`EuiButton props size l is rendered 1`] = `
 </button>
 `;
 
+exports[`EuiButton props size m is rendered 1`] = `
+<button
+  class="euiButton euiButton--primary"
+  type="button"
+>
+  <span
+    class="euiButton__content"
+  >
+    <span
+      class="euiButton__text"
+    />
+  </span>
+</button>
+`;
+
 exports[`EuiButton props size s is rendered 1`] = `
 <button
   class="euiButton euiButton--primary euiButton--small"

src/components/button/button.js

@@ -26,6 +26,7 @@ export const COLORS = Object.keys(colorToClassNameMap);
 
 const sizeToClassNameMap = {
   s: 'euiButton--small',
+  m: null,
   l: 'euiButton--large',
 };
 
@@ -198,6 +199,7 @@ EuiButton.propTypes = {
 };
 
 EuiButton.defaultProps = {
+  size: 'm',
   type: 'button',
   iconSide: 'left',
   color: 'primary',

src/components/button/index.d.ts

@@ -24,7 +24,7 @@ declare module '@elastic/eui' {
     | 'warning'
     | 'danger'
     | 'ghost';
-  export type ButtonSize = 's' | 'l';
+  export type ButtonSize = 's' | 'm' | 'l';
 
   export interface EuiButtonProps {
     iconType?: IconType;

src/components/date_picker/super_date_picker/__snapshots__/super_update_button.test.js.snap

@@ -14,6 +14,7 @@ exports[`EuiSuperUpdateButton is rendered 1`] = `
     isDisabled={false}
     isLoading={false}
     onClick={[Function]}
+    size="m"
     textProps={
       Object {
         "className": "euiSuperUpdateButton__text",
@@ -41,6 +42,7 @@ exports[`EuiSuperUpdateButton isDisabled 1`] = `
     isDisabled={true}
     isLoading={false}
     onClick={[Function]}
+    size="m"
     textProps={
       Object {
         "className": "euiSuperUpdateButton__text",
@@ -67,6 +69,7 @@ exports[`EuiSuperUpdateButton isLoading 1`] = `
     isDisabled={false}
     isLoading={true}
     onClick={[Function]}
+    size="m"
     textProps={
       Object {
         "className": "euiSuperUpdateButton__text",
@@ -94,6 +97,7 @@ exports[`EuiSuperUpdateButton needsUpdate 1`] = `
     isDisabled={false}
     isLoading={false}
     onClick={[Function]}
+    size="m"
     textProps={
       Object {
         "className": "euiSuperUpdateButton__text",