add support for insertSpaceBeforeTypeAnnotation

Author: Kingwl

src/harness/fourslash.ts

@@ -375,6 +375,7 @@ namespace FourSlash {
                 insertSpaceAfterTypeAssertion: false,
                 placeOpenBraceOnNewLineForFunctions: false,
                 placeOpenBraceOnNewLineForControlBlocks: false,
+                insertSpaceBeforeTypeAnnotation: false
             };
 
             // Open the first file by default

src/server/protocol.ts

@@ -2488,6 +2488,7 @@ namespace ts.server.protocol {
         insertSpaceBeforeFunctionParenthesis?: boolean;
         placeOpenBraceOnNewLineForFunctions?: boolean;
         placeOpenBraceOnNewLineForControlBlocks?: boolean;
+        insertSpaceBeforeTypeAnnotation?: boolean;
     }
 
     export interface CompilerOptions {

src/services/formatting/rules.ts

@@ -47,7 +47,7 @@ namespace ts.formatting {
             rule("IgnoreBeforeComment", anyToken, comments, anyContext, RuleAction.Ignore),
             rule("IgnoreAfterLineComment", SyntaxKind.SingleLineCommentTrivia, anyToken, anyContext, RuleAction.Ignore),
 
-            rule("NoSpaceBeforeColon", anyToken, SyntaxKind.ColonToken, [isNonJsxSameLineTokenContext, isNotBinaryOpContext], RuleAction.Delete),
+            rule("NotSpaceBeforeColon", anyToken, SyntaxKind.ColonToken, [isNonJsxSameLineTokenContext, isNotBinaryOpContext, isNotTypeAnnotationContext], RuleAction.Delete),
             rule("SpaceAfterColon", SyntaxKind.ColonToken, anyToken, [isNonJsxSameLineTokenContext, isNotBinaryOpContext], RuleAction.Space),
             rule("NoSpaceBeforeQuestionMark", anyToken, SyntaxKind.QuestionToken, [isNonJsxSameLineTokenContext, isNotBinaryOpContext], RuleAction.Delete),
             // insert space after '?' only when it is used in conditional operator
@@ -300,6 +300,9 @@ namespace ts.formatting {
 
             rule("SpaceAfterTypeAssertion", SyntaxKind.GreaterThanToken, anyToken, [isOptionEnabled("insertSpaceAfterTypeAssertion"), isNonJsxSameLineTokenContext, isTypeAssertionContext], RuleAction.Space),
             rule("NoSpaceAfterTypeAssertion", SyntaxKind.GreaterThanToken, anyToken, [isOptionDisabledOrUndefined("insertSpaceAfterTypeAssertion"), isNonJsxSameLineTokenContext, isTypeAssertionContext], RuleAction.Delete),
+
+            rule("SpaceBeforeTypeAnnotation", anyToken, SyntaxKind.ColonToken, [isOptionEnabled("insertSpaceBeforeTypeAnnotation"), isNonJsxSameLineTokenContext, isTypeAnnotationContext], RuleAction.Space),
+            rule("NoSpaceBeforeTypeAnnotation", anyToken, SyntaxKind.ColonToken, [isOptionDisabledOrUndefined("insertSpaceBeforeTypeAnnotation"), isNonJsxSameLineTokenContext, isTypeAnnotationContext], RuleAction.Delete),
         ];
 
         // These rules are lower in priority than user-configurable
@@ -440,6 +443,19 @@ namespace ts.formatting {
         return !isBinaryOpContext(context);
     }
 
+    function isNotTypeAnnotationContext(context: FormattingContext): boolean {
+        return !isTypeAnnotationContext(context);
+    }
+
+    function isTypeAnnotationContext(context: FormattingContext): boolean {
+        const contextKind = context.contextNode.kind;
+        return contextKind === SyntaxKind.PropertyDeclaration ||
+            contextKind === SyntaxKind.PropertySignature ||
+            contextKind === SyntaxKind.Parameter ||
+            contextKind === SyntaxKind.VariableDeclaration ||
+            isFunctionLikeKind(contextKind);
+    }
+
     function isConditionalOperatorContext(context: FormattingContext): boolean {
         return context.contextNode.kind === SyntaxKind.ConditionalExpression;
     }

src/services/types.ts

@@ -571,6 +571,7 @@ namespace ts {
         InsertSpaceBeforeFunctionParenthesis?: boolean;
         PlaceOpenBraceOnNewLineForFunctions: boolean;
         PlaceOpenBraceOnNewLineForControlBlocks: boolean;
+        insertSpaceBeforeTypeAnnotation?: boolean;
     }
 
     export interface FormatCodeSettings extends EditorSettings {
@@ -589,6 +590,7 @@ namespace ts {
         insertSpaceBeforeFunctionParenthesis?: boolean;
         placeOpenBraceOnNewLineForFunctions?: boolean;
         placeOpenBraceOnNewLineForControlBlocks?: boolean;
+        insertSpaceBeforeTypeAnnotation?: boolean;
     }
 
     export interface DefinitionInfo {

tests/baselines/reference/api/tsserverlibrary.d.ts

@@ -4211,6 +4211,7 @@ declare namespace ts {
         InsertSpaceBeforeFunctionParenthesis?: boolean;
         PlaceOpenBraceOnNewLineForFunctions: boolean;
         PlaceOpenBraceOnNewLineForControlBlocks: boolean;
+        insertSpaceBeforeTypeAnnotation?: boolean;
     }
     interface FormatCodeSettings extends EditorSettings {
         insertSpaceAfterCommaDelimiter?: boolean;
@@ -4228,6 +4229,7 @@ declare namespace ts {
         insertSpaceBeforeFunctionParenthesis?: boolean;
         placeOpenBraceOnNewLineForFunctions?: boolean;
         placeOpenBraceOnNewLineForControlBlocks?: boolean;
+        insertSpaceBeforeTypeAnnotation?: boolean;
     }
     interface DefinitionInfo {
         fileName: string;
@@ -6830,6 +6832,7 @@ declare namespace ts.server.protocol {
         insertSpaceBeforeFunctionParenthesis?: boolean;
         placeOpenBraceOnNewLineForFunctions?: boolean;
         placeOpenBraceOnNewLineForControlBlocks?: boolean;
+        insertSpaceBeforeTypeAnnotation?: boolean;
     }
     interface CompilerOptions {
         allowJs?: boolean;

tests/baselines/reference/api/typescript.d.ts

@@ -4211,6 +4211,7 @@ declare namespace ts {
         InsertSpaceBeforeFunctionParenthesis?: boolean;
         PlaceOpenBraceOnNewLineForFunctions: boolean;
         PlaceOpenBraceOnNewLineForControlBlocks: boolean;
+        insertSpaceBeforeTypeAnnotation?: boolean;
     }
     interface FormatCodeSettings extends EditorSettings {
         insertSpaceAfterCommaDelimiter?: boolean;
@@ -4228,6 +4229,7 @@ declare namespace ts {
         insertSpaceBeforeFunctionParenthesis?: boolean;
         placeOpenBraceOnNewLineForFunctions?: boolean;
         placeOpenBraceOnNewLineForControlBlocks?: boolean;
+        insertSpaceBeforeTypeAnnotation?: boolean;
     }
     interface DefinitionInfo {
         fileName: string;

tests/cases/fourslash/formattingOptionsChange.ts

@@ -9,6 +9,7 @@
 /////*insertSpaceAfterOpeningAndBeforeClosingNonemptyBrackets*/[1  ]; [ ]; []; [,];
 /////*insertSpaceAfterOpeningAndBeforeClosingTemplateStringBraces*/`${1}`;`${   1  }`
 /////*insertSpaceAfterTypeAssertion*/const bar = <Bar>    Thing.getFoo();
+/////*insertSpaceBeforeTypeAnnotation*/const bar   :   number = 1;
 /////*placeOpenBraceOnNewLineForFunctions*/class   foo   { 
 ////}
 /////*placeOpenBraceOnNewLineForControlBlocks*/if (true)   {
@@ -26,6 +27,7 @@ runTest("insertSpaceAfterOpeningAndBeforeClosingNonemptyParenthesis", "    ( 1 )
 runTest("insertSpaceAfterOpeningAndBeforeClosingNonemptyBrackets", "[ 1 ];[];[];[ , ];", "[1];[];[];[,];");
 runTest("insertSpaceAfterOpeningAndBeforeClosingTemplateStringBraces", "`${ 1 }`; `${ 1 }`", "`${1}`; `${1}`");
 runTest("insertSpaceAfterTypeAssertion", "const bar = <Bar> Thing.getFoo();", "const bar = <Bar>Thing.getFoo();");
+runTest("insertSpaceBeforeTypeAnnotation", "const bar : number = 1;", "const bar: number = 1;");
 runTest("placeOpenBraceOnNewLineForFunctions", "class foo", "class foo {");
 runTest("placeOpenBraceOnNewLineForControlBlocks", "if (true)", "if (true) {");
 runTest("insertSpaceAfterOpeningAndBeforeClosingNonemptyBraces", "{ var t = 1 }; var { a, b } = { a: 'sw', b: 'r' }; function f({ a, b }) { }", "{var t = 1}; var {a, b} = {a: 'sw', b: 'r'}; function f({a, b}) {}");

tests/cases/fourslash/fourslash.ts

@@ -97,6 +97,7 @@ declare namespace FourSlashInterface {
         InsertSpaceAfterTypeAssertion: boolean;
         PlaceOpenBraceOnNewLineForFunctions: boolean;
         PlaceOpenBraceOnNewLineForControlBlocks: boolean;
+        insertSpaceBeforeTypeAnnotation: boolean;
         [s: string]: boolean | number | string | undefined;
     }
     interface Range {