use Transformer Replacements

fable-compiler · Sep 18, 2024 · 72fe819 · 72fe819
1 parent 3c9c5c0
commit 72fe819
Show file tree

Hide file tree

Showing 3 changed files with 21 additions and 10 deletions.
diff --git a/build.sh b/build.sh
@@ -2,3 +2,5 @@
 
 dotnet tool restore
 dotnet run --project src/Fable.Build/Fable.Build.fsproj -- $@
+# dotnet run --project src/Fable.Build/Fable.Build.fsproj -- test javascript
+# dotnet run --project src/Fable.Build/Fable.Build.fsproj -- test typescript
diff --git a/src/Fable.Transforms/Replacements.fs b/src/Fable.Transforms/Replacements.fs
@@ -1449,7 +1449,6 @@ let implementedStringFunctions =
         [|
             "Compare"
             "CompareTo"
-            "EndsWith"
             "Format"
             "IndexOfAny"
             "Insert"
@@ -1503,12 +1502,15 @@ let strings (com: ICompiler) (ctx: Context) r t (i: CallInfo) (thisArg: Expr opt
 
         let left = Helper.InstanceCall(c, "indexOf", Int32.Number, [ arg ])
         makeEqOp r left (makeIntConst 0) BinaryGreaterOrEqual |> Some
-    | "StartsWith", Some c, [ _str ] ->
-        let left = Helper.InstanceCall(c, "indexOf", Int32.Number, args)
-        makeEqOp r left (makeIntConst 0) BinaryEqual |> Some
+    | "StartsWith", Some c, [ _str ] -> Helper.InstanceCall(c, "startsWith", Boolean, args) |> Some
     | "StartsWith", Some c, [ _str; _comp ] ->
         Helper.LibCall(com, "String", "startsWith", t, args, i.SignatureArgTypes, thisArg = c, ?loc = r)
         |> Some
+    | "EndsWith", Some c, [ _str ] -> Helper.InstanceCall(c, "endsWith", Boolean, args) |> Some
+    | "EndsWith", Some c, [ _str; _comp ] ->
+        Helper.LibCall(com, "String", "endsWith", t, args, i.SignatureArgTypes, thisArg = c, ?loc = r)
+        |> Some
+
     | ReplaceName [ "ToUpper", "toLocaleUpperCase"
                     "ToUpperInvariant", "toUpperCase"
                     "ToLower", "toLocaleLowerCase"

diff --git a/src/fable-library-ts/String.ts b/src/fable-library-ts/String.ts
@@ -64,12 +64,25 @@ export function compareTo(x: string, y: string) {
 }
 
 export function startsWith(str: string, pattern: string, ic: number) {
+  if (ic=== StringComparison.Ordinal){ // to avoid substring allocation
+    return str.startsWith(pattern) ;
+  }
   if (str.length >= pattern.length) {
     return cmp(str.substr(0, pattern.length), pattern, ic) === 0;
   }
   return false;
 }
 
+export function endsWith(str: string, pattern: string, ic: number) {
+  if (ic=== StringComparison.Ordinal){ // to avoid substring allocation
+    return str.endsWith(pattern) ;
+  }
+  if (str.length >= pattern.length) {
+    return cmp(str.substr(str.length-pattern.length, pattern.length), pattern, ic) === 0;
+  }
+  return false;
+}
+
 export function indexOfAny(str: string, anyOf: string[], ...args: number[]) {
   if (str == null || str === "") {
     return -1;
@@ -374,12 +387,6 @@ export function format(str: string | object, ...args: any[]) {
   });
 }
 
-export function endsWith(str: string, pattern: string, ic: number) {
-  if (str.length >= pattern.length) {
-    return cmp(str.substr(str.length-1-pattern.length, pattern.length), pattern, ic) === 0;
-  }
-  return false;
-}
 
 export function initialize(n: number, f: (i: number) => string) {
   if (n < 0) {