Script Loader: Introduce wp_add_inline_script().

This new function can be used to add inline JavaScript before and after enqueued scripts, just like `wp_add_inline_style()` works for CSS.

Props atimmer, abiralneupane, ocean90, swissspidy.
Fixes #14853.

git-svn-id: https://develop.svn.wordpress.org/trunk@36633 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/functions.wp-scripts.php

@@ -85,6 +85,35 @@ function wp_print_scripts( $handles = false ) {
 	return wp_scripts()->do_items( $handles );
 }
 
+/**
+ * Add extra code to a registered script.
+ *
+ * Code will only be added if the script in already in the queue.
+ * Accepts a string $data containing the Code. If two or more code blocks
+ * are added to the same script $handle, they will be printed in the order
+ * they were added, i.e. the latter added code can redeclare the previous.
+ *
+ * @since 4.5.0
+ *
+ * @see WP_Scripts::add_inline_script()
+ *
+ * @param string $handle   Name of the script to add the inline script to. Must be lowercase.
+ * @param string $data     String containing the javascript to be added.
+ * @param string $position Optional. Whether to add the inline script before the handle
+ *                         or after. Default 'after'.
+ * @return bool True on success, false on failure.
+ */
+function wp_add_inline_script( $handle, $data, $position = 'after' ) {
+	_wp_scripts_maybe_doing_it_wrong( __FUNCTION__ );
+
+	if ( false !== stripos( $data, '</script>' ) ) {
+		_doing_it_wrong( __FUNCTION__, __( 'Do not pass script tags to wp_add_inline_script().' ), '4.5.0' );
+		$data = trim( preg_replace( '#<script[^>]*>(.*)</script>#is', '$1', $data ) );
+	}
+
+	return wp_scripts()->add_inline_script( $handle, $data, $position );
+}
+
 /**
  * Register a new script.
  *