space-before-function-paren

Adding option InsertSpaceBeforeFunctionParenthesis
Should be optional
Typically used to support http://eslint.org/docs/rules/space-before-function-paren

Fixes #12234

Author: Andrew Ochsner

src/server/protocol.ts

@@ -2200,6 +2200,7 @@ namespace ts.server.protocol {
         insertSpaceAfterOpeningAndBeforeClosingNonemptyBrackets?: boolean;
         insertSpaceAfterOpeningAndBeforeClosingTemplateStringBraces?: boolean;
         insertSpaceAfterOpeningAndBeforeClosingJsxExpressionBraces?: boolean;
+        insertSpaceBeforeFunctionParenthesis?: boolean;
         placeOpenBraceOnNewLineForFunctions?: boolean;
         placeOpenBraceOnNewLineForControlBlocks?: boolean;
     }

src/server/utilities.ts

@@ -87,6 +87,7 @@ namespace ts.server {
             insertSpaceAfterOpeningAndBeforeClosingNonemptyBrackets: false,
             insertSpaceAfterOpeningAndBeforeClosingTemplateStringBraces: false,
             insertSpaceAfterOpeningAndBeforeClosingJsxExpressionBraces: false,
+            insertSpaceBeforeFunctionParenthesis: false,
             placeOpenBraceOnNewLineForFunctions: false,
             placeOpenBraceOnNewLineForControlBlocks: false,
         };

src/services/formatting/rules.ts

@@ -87,6 +87,7 @@ namespace ts.formatting {
         public SpaceAfterLetConstInVariableDeclaration: Rule;
         public NoSpaceBeforeOpenParenInFuncCall: Rule;
         public SpaceAfterFunctionInFuncDecl: Rule;
+        public SpaceBeforeOpenParenInFuncDecl: Rule;
         public NoSpaceBeforeOpenParenInFuncDecl: Rule;
         public SpaceAfterVoidOperator: Rule;
 
@@ -329,6 +330,7 @@ namespace ts.formatting {
             this.SpaceAfterLetConstInVariableDeclaration = new Rule(RuleDescriptor.create4(Shared.TokenRange.FromTokens([SyntaxKind.LetKeyword, SyntaxKind.ConstKeyword]), Shared.TokenRange.Any), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext, Rules.IsStartOfVariableDeclarationList), RuleAction.Space));
             this.NoSpaceBeforeOpenParenInFuncCall = new Rule(RuleDescriptor.create2(Shared.TokenRange.Any, SyntaxKind.OpenParenToken), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext, Rules.IsFunctionCallOrNewContext, Rules.IsPreviousTokenNotComma), RuleAction.Delete));
             this.SpaceAfterFunctionInFuncDecl = new Rule(RuleDescriptor.create3(SyntaxKind.FunctionKeyword, Shared.TokenRange.Any), RuleOperation.create2(new RuleOperationContext(Rules.IsFunctionDeclContext), RuleAction.Space));
+            this.SpaceBeforeOpenParenInFuncDecl = new Rule(RuleDescriptor.create2(Shared.TokenRange.Any, SyntaxKind.OpenParenToken), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext, Rules.IsFunctionDeclContext), RuleAction.Space));
             this.NoSpaceBeforeOpenParenInFuncDecl = new Rule(RuleDescriptor.create2(Shared.TokenRange.Any, SyntaxKind.OpenParenToken), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext, Rules.IsFunctionDeclContext), RuleAction.Delete));
             this.SpaceAfterVoidOperator = new Rule(RuleDescriptor.create3(SyntaxKind.VoidKeyword, Shared.TokenRange.Any), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext, Rules.IsVoidOpContext), RuleAction.Space));
 
@@ -462,7 +464,6 @@ namespace ts.formatting {
                 this.NoSpaceBeforeOpenBracket,
                 this.NoSpaceAfterCloseBracket,
                 this.SpaceAfterSemicolon,
-                this.NoSpaceBeforeOpenParenInFuncDecl,
                 this.SpaceBetweenStatements, this.SpaceAfterTryFinally
             ];
 

src/services/formatting/rulesProvider.ts

@@ -128,6 +128,13 @@ namespace ts.formatting {
                 rules.push(this.globalRules.NoSpaceAfterBinaryOperator);
             }
 
+            if (options.insertSpaceBeforeFunctionParenthesis) {
+                rules.push(this.globalRules.SpaceBeforeOpenParenInFuncDecl);
+            }
+            else {
+                rules.push(this.globalRules.NoSpaceBeforeOpenParenInFuncDecl);
+            }
+
             if (options.placeOpenBraceOnNewLineForControlBlocks) {
                 rules.push(this.globalRules.NewLineBeforeOpenBraceInControl);
             }

src/services/types.ts

@@ -426,6 +426,7 @@ namespace ts {
         InsertSpaceAfterOpeningAndBeforeClosingTemplateStringBraces: boolean;
         InsertSpaceAfterOpeningAndBeforeClosingJsxExpressionBraces?: boolean;
         InsertSpaceAfterTypeAssertion?: boolean;
+        InsertSpaceBeforeFunctionParenthesis?: boolean;
         PlaceOpenBraceOnNewLineForFunctions: boolean;
         PlaceOpenBraceOnNewLineForControlBlocks: boolean;
     }
@@ -442,6 +443,7 @@ namespace ts {
         insertSpaceAfterOpeningAndBeforeClosingTemplateStringBraces?: boolean;
         insertSpaceAfterOpeningAndBeforeClosingJsxExpressionBraces?: boolean;
         insertSpaceAfterTypeAssertion?: boolean;
+        insertSpaceBeforeFunctionParenthesis?: boolean;
         placeOpenBraceOnNewLineForFunctions?: boolean;
         placeOpenBraceOnNewLineForControlBlocks?: boolean;
     }

tests/cases/fourslash/formattingSpaceBeforeFunctionParen.ts

@@ -0,0 +1,13 @@
+/// <reference path='fourslash.ts' />
+
+/////*1*/function foo() { }
+/////*2*/function boo  () { }
+
+format.setOption("InsertSpaceBeforeFunctionParenthesis", true);
+
+format.document();
+
+goTo.marker('1');
+verify.currentLineContentIs('function foo () { }');
+goTo.marker('2');
+verify.currentLineContentIs('function boo () { }');