Make sam header parser same as bam-js

src/sam.ts

@@ -1,20 +1,19 @@
-export type HeaderDataItem = {
-  tag: string
-  data: Array<{ tag: string; value: string }>
-}
-
-export function parseHeaderText(text: string): HeaderDataItem[] {
+export function parseHeaderText(text: string) {
   const lines = text.split(/\r?\n/)
-  const data: HeaderDataItem[] = []
-  lines.forEach(line => {
+  const data: { tag: string; data: { tag: string; value: string }[] }[] = []
+  for (const line of lines) {
     const [tag, ...fields] = line.split(/\t/)
-    const parsedFields = fields.map(f => {
-      const [fieldTag, value] = f.split(':', 2)
-      return { tag: fieldTag, value }
-    })
     if (tag) {
-      data.push({ tag: tag.substr(1), data: parsedFields })
+      data.push({
+        tag: tag.slice(1),
+        data: fields.map(f => {
+          const r = f.indexOf(':')
+          const fieldTag = f.slice(0, r)
+          const value = f.slice(r + 1)
+          return { tag: fieldTag, value }
+        }),
+      })
     }
-  })
+  }
   return data
 }