$mol_sourcemap fixes

sourcemap/builder.ts

@@ -126,14 +126,16 @@ namespace $ {
 
 					if (segment.length >= 5) {
 						const nameIndex = segment[4]!
-						const name = raw.names[nameIndex]
-						let mergedNameIndex = name_indexes.get(name)
-						if (mergedNameIndex === undefined) {
-							mergedNameIndex = names.length
-							name_indexes.set(name, mergedNameIndex)
-							names.push(name)
+						const name = raw.names?.[nameIndex]
+						if (name !== undefined) {
+							let mergedNameIndex = name_indexes.get(name)
+							if (mergedNameIndex === undefined) {
+								mergedNameIndex = names.length
+								name_indexes.set(name, mergedNameIndex)
+								names.push(name)
+							}
+							mergedSegment.push(mergedNameIndex)
 						}
-						mergedSegment.push(mergedNameIndex)
 					}
 
 					mergedLine.push(mergedSegment)

sourcemap/dataurl.ts

@@ -8,20 +8,26 @@ namespace $ {
 
 		if (index === -1) return undefined
 
-		data = data.substring(index)
+		data = data.substring(index + prefix.length)
 
-		if (data.endsWith(end_comment)) data = data.substring(0, end_comment.length)
+		if (data.endsWith(end_comment)) data = data.substring(0, data.length - end_comment.length)
 
 		const decoded = this.decodeURIComponent(data)
-		const map = JSON.parse(decoded) as $mol_sourcemap_raw | null
 
-		if (! map) return undefined
+		try {
+			const map = JSON.parse(decoded) as $mol_sourcemap_raw | null
 
-		if (typeof map.mappings === 'string' && map.mappings.startsWith(';;')) {
-			map.mappings = map.mappings.substring(2)
-		}
+			if (! map) return undefined
+
+			if (typeof map.mappings === 'string' && map.mappings.startsWith(';;')) {
+				map.mappings = map.mappings.substring(2)
+			}
 
-		return map
+			return map
+		} catch (e) {
+			if (e instanceof Error) e.message += ', origin=' + decoded
+			$mol_fail_hidden(e)
+		}
 	}
 
 	export function $mol_sourcemap_dataurl_encode(this: $, map: $mol_sourcemap_raw, type = 'js' as 'js' | 'css') {

sourcemap/sourcemap.ts

@@ -7,7 +7,7 @@ namespace $ {
 	export interface $mol_sourcemap_raw {
 		version: number
 		sources: string[]
-		names: string[]
+		names?: string[]
 		sourceRoot?: string
 		sourcesContent?: (string | null)[]
 		mappings: string | $mol_sourcemap_line[]

tree2/text/to/sourcemap/sourcemap.ts

@@ -90,7 +90,6 @@ namespace $ {
 
 		const map: $mol_sourcemap_raw = {
 			version: 3,
-			names: [],
 			sources: [ ... file_sources.keys() ],
 			sourcesContent: [ ... file_sources.values() ],
 			mappings,