Fix 53482 : Preserve newline/space behavior

src/compiler/emitter.ts

@@ -862,6 +862,7 @@ export function emitFiles(resolver: EmitResolver, host: EmitHost, targetSourceFi
             inlineSources: compilerOptions.inlineSources,
             extendedDiagnostics: compilerOptions.extendedDiagnostics,
             writeBundleFileInfo: !!bundleBuildInfo,
+            preserveSourceNewlines: true,
             relativeToBuildInfo
         };
 
@@ -4866,20 +4867,27 @@ export function createPrinter(printerOptions: PrinterOptions = {}, handlers: Pri
     }
 
     function emitEmbeddedStatement(parent: Node, node: Statement) {
-        if (isBlock(node) || getEmitFlags(parent) & EmitFlags.SingleLine) {
+        const lines = getLeadingLineTerminatorCount(parent, node, ListFormat.None);
+        if (isBlock(node) || getEmitFlags(parent) & EmitFlags.SingleLine || !lines) {
             writeSpace();
             emit(node);
         }
         else {
-            writeLine();
-            increaseIndent();
-            if (isEmptyStatement(node)) {
-                pipelineEmit(EmitHint.EmbeddedStatement, node);
+            if (lines) {
+                writeLine(lines);
+                increaseIndent();
+                if (isEmptyStatement(node)) {
+                    pipelineEmit(EmitHint.EmbeddedStatement, node);
+                }
+                else {
+                    emit(node);
+                }
+                decreaseIndent();
             }
             else {
+                writeSpace();
                 emit(node);
             }
-            decreaseIndent();
         }
     }
 

tests/baselines/reference/preserveSpace.js

@@ -0,0 +1,47 @@
+//// [preserveSpace.ts]
+function f() {
+  return [].filter(x => {
+        if (!x) return false; // testing comments
+        if (x)
+            return true; // testing comments
+        if (x) {
+            return false; // testing comments
+        } else {
+            console.log("here"); // testing comments
+        }
+        let i: number = 0;
+        while (i > 0) i = i - 1;
+        do console.log("here");
+        while (false);
+
+        try {
+            return true;
+        } catch (e) {
+            return false;
+        }
+  });
+}
+
+//// [preserveSpace.js]
+function f() {
+    return [].filter(function (x) {
+        if (!x) return false; // testing comments
+        if (x)
+            return true; // testing comments
+        if (x) {
+            return false; // testing comments
+        } else {
+            console.log("here"); // testing comments
+        }
+        var i = 0;
+        while (i > 0) i = i - 1;
+        do console.log("here");
+        while (false);
+
+        try {
+            return true;
+        } catch (e) {
+            return false;
+        }
+    });
+}

tests/baselines/reference/preserveSpace.symbols

@@ -0,0 +1,50 @@
+=== tests/cases/conformance/preserveSpace.ts ===
+function f() {
+>f : Symbol(f, Decl(preserveSpace.ts, 0, 0))
+
+  return [].filter(x => {
+>[].filter : Symbol(Array.filter, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>filter : Symbol(Array.filter, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>x : Symbol(x, Decl(preserveSpace.ts, 1, 19))
+
+        if (!x) return false; // testing comments
+>x : Symbol(x, Decl(preserveSpace.ts, 1, 19))
+
+        if (x)
+>x : Symbol(x, Decl(preserveSpace.ts, 1, 19))
+
+            return true; // testing comments
+        if (x) {
+>x : Symbol(x, Decl(preserveSpace.ts, 1, 19))
+
+            return false; // testing comments
+        } else {
+            console.log("here"); // testing comments
+>console.log : Symbol(Console.log, Decl(lib.dom.d.ts, --, --))
+>console : Symbol(console, Decl(lib.dom.d.ts, --, --))
+>log : Symbol(Console.log, Decl(lib.dom.d.ts, --, --))
+        }
+        let i: number = 0;
+>i : Symbol(i, Decl(preserveSpace.ts, 10, 11))
+
+        while (i > 0) i = i - 1;
+>i : Symbol(i, Decl(preserveSpace.ts, 10, 11))
+>i : Symbol(i, Decl(preserveSpace.ts, 10, 11))
+>i : Symbol(i, Decl(preserveSpace.ts, 10, 11))
+
+        do console.log("here");
+>console.log : Symbol(Console.log, Decl(lib.dom.d.ts, --, --))
+>console : Symbol(console, Decl(lib.dom.d.ts, --, --))
+>log : Symbol(Console.log, Decl(lib.dom.d.ts, --, --))
+
+        while (false);
+
+        try {
+            return true;
+        } catch (e) {
+>e : Symbol(e, Decl(preserveSpace.ts, 17, 17))
+
+            return false;
+        }
+  });
+}

tests/baselines/reference/preserveSpace.types

@@ -0,0 +1,73 @@
+=== tests/cases/conformance/preserveSpace.ts ===
+function f() {
+>f : () => any[]
+
+  return [].filter(x => {
+>[].filter(x => {        if (!x) return false; // testing comments        if (x)            return true; // testing comments        if (x) {            return false; // testing comments        } else {            console.log("here"); // testing comments        }        let i: number = 0;        while (i > 0) i = i - 1;        do console.log("here");        while (false);        try {            return true;        } catch (e) {            return false;        }  }) : any[]
+>[].filter : { <S extends any>(predicate: (value: any, index: number, array: any[]) => value is S, thisArg?: any): S[]; (predicate: (value: any, index: number, array: any[]) => unknown, thisArg?: any): any[]; }
+>[] : undefined[]
+>filter : { <S extends any>(predicate: (value: any, index: number, array: any[]) => value is S, thisArg?: any): S[]; (predicate: (value: any, index: number, array: any[]) => unknown, thisArg?: any): any[]; }
+>x => {        if (!x) return false; // testing comments        if (x)            return true; // testing comments        if (x) {            return false; // testing comments        } else {            console.log("here"); // testing comments        }        let i: number = 0;        while (i > 0) i = i - 1;        do console.log("here");        while (false);        try {            return true;        } catch (e) {            return false;        }  } : (x: any) => boolean
+>x : any
+
+        if (!x) return false; // testing comments
+>!x : boolean
+>x : any
+>false : false
+
+        if (x)
+>x : any
+
+            return true; // testing comments
+>true : true
+
+        if (x) {
+>x : any
+
+            return false; // testing comments
+>false : false
+
+        } else {
+            console.log("here"); // testing comments
+>console.log("here") : void
+>console.log : (...data: any[]) => void
+>console : Console
+>log : (...data: any[]) => void
+>"here" : "here"
+        }
+        let i: number = 0;
+>i : number
+>0 : 0
+
+        while (i > 0) i = i - 1;
+>i > 0 : boolean
+>i : number
+>0 : 0
+>i = i - 1 : number
+>i : number
+>i - 1 : number
+>i : number
+>1 : 1
+
+        do console.log("here");
+>console.log("here") : void
+>console.log : (...data: any[]) => void
+>console : Console
+>log : (...data: any[]) => void
+>"here" : "here"
+
+        while (false);
+>false : false
+
+        try {
+            return true;
+>true : true
+
+        } catch (e) {
+>e : any
+
+            return false;
+>false : false
+        }
+  });
+}

tests/cases/conformance/preserveSpace.ts

@@ -0,0 +1,22 @@
+function f() {
+  return [].filter(x => {
+        if (!x) return false; // testing comments
+        if (x)
+            return true; // testing comments
+        if (x) {
+            return false; // testing comments
+        } else {
+            console.log("here"); // testing comments
+        }
+        let i: number = 0;
+        while (i > 0) i = i - 1;
+        do console.log("here");
+        while (false);
+
+        try {
+            return true;
+        } catch (e) {
+            return false;
+        }
+  });
+}