Allow JS functions in TinyMCE $initArray

[janfabry]

r16090 allowed booleans, JSON-encoded arrays and objects to be passed to the TinyMCE configuration, by not wrapping them in quotes. If the check for { and [ could be expanded to include (, we could also pass anonymous functions (of the form (function() { if ( someClientSideProperty ) return 'a'; return 'b'; })()), which allows integration of client-side information in the TinyMCE configuration. This would greatly increase the flexibility of plugins to pass extra information to TinyMCE without jumping through hoops.

This would be sooo neat.

Ran into the issue myself, and I had to do weird a workaround to get multi-dimensional objects in there, aka:

		// ...
		$campaign = array(
			'publish' => __('Launch', 'sem-backend'),
			'publishNow' => __('Launch:', 'sem-backend'),
			'publishOn' => __('Launch on:', 'sem-backend'),
			'publishOnPast' => __('Launched on:', 'sem-backend'),
			'unit' => __('Coupon left', 'sem-backend'),
			'units' => __('Coupons left', 'sem-backend'),
			);
		
		$extra_captions = compact('defaults', 'product', 'campaign');
		$extra_captions = apply_filters('sem_backend_localize_js', $extra_captions);
		
		foreach ( $extra_captions as $key => $extra ) {
			$data = "\n\nsem_backendL10n['$key'] = {\n";
			$eol = '';
			foreach ( $extra as $var => $val ) {
				$data .= "$eol\t$var: \"" . esc_js($val) . '"';
				$eol = ",\n";
			}
			$data .= "\n};\n";
			$data .= "try{convertEntities(sem_backendL10n.$key);}catch(e){};\n";
			$captions['l10n_print_after'] .= $data;
		}
		
		wp_localize_script('sb-data-admin', 'sem_backendL10n', $captions);

Indeed, my proposal covered only TinyMCE init, but there are other places where Javascript is generated, like in WP_Script::print_script_l10n(), which is used more and more as a generic data passing method, not just for localization.

We should keep backwards compatibility in mind: I wouldn't want a string like '(Closed)' to be interpreted as a non-string. But the same goes for '[Closed]' and '{Closed}', which will not be embedded in quotes now, even if they should be. Maybe add " to the list too, so once can "self-escape" and pass a variable as '"[This is a string, not an array]"'?

(In [17522]) Allow JS functions in the TinyMCE init array, fixes #15596