comments

src/compiler/compile/nodes/Element.ts

@@ -219,7 +219,11 @@ export default class Element extends Node {
 			if (this.name === 'pre' || this.name === 'textarea') {
 				const first = info.children[0];
 				if (first && first.type === 'Text') {
-					// The leading newline character should be stripped.
+					// The leading newline character needs to be stripped because of a qirk,
+					// it is ignored by browsers if the tag and its contents are set through
+					// innerHTML (NOT if set through the innerHTML of the tag or dynamically).
+					// Therefore strip it here but add it back in the appropriate
+					// places if there's another newline afterwards.
 					// see https://html.spec.whatwg.org/multipage/syntax.html#element-restrictions
 					// see https://html.spec.whatwg.org/multipage/grouping-content.html#the-pre-element
 					first.data = first.data.replace(start_newline, '');

src/compiler/compile/render_dom/wrappers/Element/index.ts

@@ -1114,6 +1114,9 @@ export default class ElementWrapper extends Wrapper {
 function to_html(wrappers: Array<ElementWrapper | TextWrapper | MustacheTagWrapper | RawMustacheTagWrapper>, block: Block, literal: any, state: any, can_use_raw_text?: boolean) {
 	wrappers.forEach(wrapper => {
 		if (wrapper instanceof TextWrapper) {
+			// Don't add the <pre>/<textare> newline logic here because pre/textarea.innerHTML
+			// would keep the leading newline, too, only someParent.innerHTML = '..<pre/textarea>..' won't
+
 			if ((wrapper as TextWrapper).use_space()) state.quasi.value.raw += ' ';
 
 			const parent = wrapper.node.parent as Element;