restore startsWith

aozgaa · aozgaa · commit d38ee1eaf71f · 2017-05-03T13:26:24.000-07:00
diff --git a/src/compiler/core.ts b/src/compiler/core.ts
@@ -1729,8 +1729,8 @@ namespace ts {
     }
 
     /* @internal */
-    export function startsWith(str: string, prefix: string): boolean {
-        return str.indexOf(prefix) === 0;
+    export function startsWith(str: string, prefix: string | undefined): boolean {
+        return str.lastIndexOf(prefix, 0) === 0;
     }
 
     /* @internal */

Original file line number	Diff line number	Diff line change
`@@ -1729,8 +1729,8 @@ namespace ts {`
`1729`	`1729`	`}`
`1730`	`1730`
`1731`	`1731`	`/* @internal */`
`1732`		`- export function startsWith(str: string, prefix: string): boolean {`
`1733`		`- return str.indexOf(prefix) === 0;`
	`1732`	`+ export function startsWith(str: string, prefix: string \| undefined): boolean {`
	`1733`	`+ return str.lastIndexOf(prefix, 0) === 0;`
`1734`	`1734`	`}`
`1735`	`1735`
`1736`	`1736`	`/* @internal */`