diff --git a/src/compiler/factory.ts b/src/compiler/factory.ts index c7fe7d70574..7f758f70794 100644 --- a/src/compiler/factory.ts +++ b/src/compiler/factory.ts @@ -3055,4 +3055,194 @@ namespace ts { function tryGetModuleNameFromDeclaration(declaration: ImportEqualsDeclaration | ImportDeclaration | ExportDeclaration, host: EmitHost, resolver: EmitResolver, compilerOptions: CompilerOptions) { return tryGetModuleNameFromFile(resolver.getExternalModuleFileFromDeclaration(declaration), host, compilerOptions); } + + export function convertForOf(node: ForOfStatement, convertedLoopBodyStatements: Statement[], + visitor: (node: Node) => VisitResult, + enableSubstitutionsForBlockScopedBindings: () => void, + context: TransformationContext, + convertObjectRest?: boolean): ForStatement | ForOfStatement { + // The following ES6 code: + // + // for (let v of expr) { } + // + // should be emitted as + // + // for (var _i = 0, _a = expr; _i < _a.length; _i++) { + // var v = _a[_i]; + // } + // + // where _a and _i are temps emitted to capture the RHS and the counter, + // respectively. + // When the left hand side is an expression instead of a let declaration, + // the "let v" is not emitted. + // When the left hand side is a let/const, the v is renamed if there is + // another v in scope. + // Note that all assignments to the LHS are emitted in the body, including + // all destructuring. + // Note also that because an extra statement is needed to assign to the LHS, + // for-of bodies are always emitted as blocks. + + const expression = visitNode(node.expression, visitor, isExpression); + const initializer = node.initializer; + const statements: Statement[] = []; + + // In the case where the user wrote an identifier as the RHS, like this: + // + // for (let v of arr) { } + // + // we don't want to emit a temporary variable for the RHS, just use it directly. + const counter = convertObjectRest ? undefined : createLoopVariable(); + const rhsReference = expression.kind === SyntaxKind.Identifier + ? createUniqueName((expression).text) + : createTempVariable(/*recordTempVariable*/ undefined); + const elementAccess = convertObjectRest ? rhsReference : createElementAccess(rhsReference, counter); + + // Initialize LHS + // var v = _a[_i]; + if (isVariableDeclarationList(initializer)) { + if (initializer.flags & NodeFlags.BlockScoped) { + enableSubstitutionsForBlockScopedBindings(); + } + + const firstOriginalDeclaration = firstOrUndefined(initializer.declarations); + if (firstOriginalDeclaration && isBindingPattern(firstOriginalDeclaration.name)) { + // This works whether the declaration is a var, let, or const. + // It will use rhsIterationValue _a[_i] as the initializer. + const declarations = flattenVariableDestructuring( + firstOriginalDeclaration, + elementAccess, + visitor, + /*recordTempVariable*/ undefined, + convertObjectRest + ); + + const declarationList = createVariableDeclarationList(declarations, /*location*/ initializer); + setOriginalNode(declarationList, initializer); + + // Adjust the source map range for the first declaration to align with the old + // emitter. + const firstDeclaration = declarations[0]; + const lastDeclaration = lastOrUndefined(declarations); + setSourceMapRange(declarationList, createRange(firstDeclaration.pos, lastDeclaration.end)); + + statements.push( + createVariableStatement( + /*modifiers*/ undefined, + declarationList + ) + ); + } + else { + // The following call does not include the initializer, so we have + // to emit it separately. + statements.push( + createVariableStatement( + /*modifiers*/ undefined, + setOriginalNode( + createVariableDeclarationList([ + createVariableDeclaration( + firstOriginalDeclaration ? firstOriginalDeclaration.name : createTempVariable(/*recordTempVariable*/ undefined), + /*type*/ undefined, + createElementAccess(rhsReference, counter) + ) + ], /*location*/ moveRangePos(initializer, -1)), + initializer + ), + /*location*/ moveRangeEnd(initializer, -1) + ) + ); + } + } + else { + // Initializer is an expression. Emit the expression in the body, so that it's + // evaluated on every iteration. + const assignment = createAssignment(initializer, elementAccess); + if (isDestructuringAssignment(assignment)) { + // This is a destructuring pattern, so we flatten the destructuring instead. + statements.push( + createStatement( + flattenDestructuringAssignment( + context, + assignment, + /*needsValue*/ false, + context.hoistVariableDeclaration, + visitor, + convertObjectRest + ) + ) + ); + } + else { + // Currently there is not way to check that assignment is binary expression of destructing assignment + // so we have to cast never type to binaryExpression + (assignment).end = initializer.end; + statements.push(createStatement(assignment, /*location*/ moveRangeEnd(initializer, -1))); + } + } + + let bodyLocation: TextRange; + let statementsLocation: TextRange; + if (convertedLoopBodyStatements) { + addRange(statements, convertedLoopBodyStatements); + } + else { + const statement = visitNode(node.statement, visitor, isStatement); + if (isBlock(statement)) { + addRange(statements, statement.statements); + bodyLocation = statement; + statementsLocation = statement.statements; + } + else { + statements.push(statement); + } + } + + // The old emitter does not emit source maps for the expression + setEmitFlags(expression, EmitFlags.NoSourceMap | getEmitFlags(expression)); + + // The old emitter does not emit source maps for the block. + // We add the location to preserve comments. + const body = createBlock( + createNodeArray(statements, /*location*/ statementsLocation), + /*location*/ bodyLocation + ); + + setEmitFlags(body, EmitFlags.NoSourceMap | EmitFlags.NoTokenSourceMaps); + + let forStatement: ForStatement | ForOfStatement; + if(convertObjectRest) { + + forStatement = createForOf( + createVariableDeclarationList([ + createVariableDeclaration(rhsReference, /*type*/ undefined, /*initializer*/ undefined, /*location*/ node.expression) + ], /*location*/ node.expression), + node.expression, + body, + /*location*/ node + ); + } + else { + forStatement = createFor( + setEmitFlags( + createVariableDeclarationList([ + createVariableDeclaration(counter, /*type*/ undefined, createLiteral(0), /*location*/ moveRangePos(node.expression, -1)), + createVariableDeclaration(rhsReference, /*type*/ undefined, expression, /*location*/ node.expression) + ], /*location*/ node.expression), + EmitFlags.NoHoisting + ), + createLessThan( + counter, + createPropertyAccess(rhsReference, "length"), + /*location*/ node.expression + ), + createPostfixIncrement(counter, /*location*/ node.expression), + body, + /*location*/ node + ); + } + + // Disable trailing source maps for the OpenParenToken to align source map emit with the old emitter. + setEmitFlags(forStatement, EmitFlags.NoTokenTrailingSourceMaps); + return forStatement; + } } diff --git a/src/compiler/transformers/es2015.ts b/src/compiler/transformers/es2015.ts index e262b413b4c..76ea6b2ddd0 100644 --- a/src/compiler/transformers/es2015.ts +++ b/src/compiler/transformers/es2015.ts @@ -1926,171 +1926,7 @@ namespace ts { } function convertForOfToFor(node: ForOfStatement, convertedLoopBodyStatements: Statement[]): ForStatement { - // The following ES6 code: - // - // for (let v of expr) { } - // - // should be emitted as - // - // for (var _i = 0, _a = expr; _i < _a.length; _i++) { - // var v = _a[_i]; - // } - // - // where _a and _i are temps emitted to capture the RHS and the counter, - // respectively. - // When the left hand side is an expression instead of a let declaration, - // the "let v" is not emitted. - // When the left hand side is a let/const, the v is renamed if there is - // another v in scope. - // Note that all assignments to the LHS are emitted in the body, including - // all destructuring. - // Note also that because an extra statement is needed to assign to the LHS, - // for-of bodies are always emitted as blocks. - - const expression = visitNode(node.expression, visitor, isExpression); - const initializer = node.initializer; - const statements: Statement[] = []; - - // In the case where the user wrote an identifier as the RHS, like this: - // - // for (let v of arr) { } - // - // we don't want to emit a temporary variable for the RHS, just use it directly. - const counter = createLoopVariable(); - const rhsReference = expression.kind === SyntaxKind.Identifier - ? createUniqueName((expression).text) - : createTempVariable(/*recordTempVariable*/ undefined); - - // Initialize LHS - // var v = _a[_i]; - if (isVariableDeclarationList(initializer)) { - if (initializer.flags & NodeFlags.BlockScoped) { - enableSubstitutionsForBlockScopedBindings(); - } - - const firstOriginalDeclaration = firstOrUndefined(initializer.declarations); - if (firstOriginalDeclaration && isBindingPattern(firstOriginalDeclaration.name)) { - // This works whether the declaration is a var, let, or const. - // It will use rhsIterationValue _a[_i] as the initializer. - const declarations = flattenVariableDestructuring( - firstOriginalDeclaration, - createElementAccess(rhsReference, counter), - visitor - ); - - const declarationList = createVariableDeclarationList(declarations, /*location*/ initializer); - setOriginalNode(declarationList, initializer); - - // Adjust the source map range for the first declaration to align with the old - // emitter. - const firstDeclaration = declarations[0]; - const lastDeclaration = lastOrUndefined(declarations); - setSourceMapRange(declarationList, createRange(firstDeclaration.pos, lastDeclaration.end)); - - statements.push( - createVariableStatement( - /*modifiers*/ undefined, - declarationList - ) - ); - } - else { - // The following call does not include the initializer, so we have - // to emit it separately. - statements.push( - createVariableStatement( - /*modifiers*/ undefined, - setOriginalNode( - createVariableDeclarationList([ - createVariableDeclaration( - firstOriginalDeclaration ? firstOriginalDeclaration.name : createTempVariable(/*recordTempVariable*/ undefined), - /*type*/ undefined, - createElementAccess(rhsReference, counter) - ) - ], /*location*/ moveRangePos(initializer, -1)), - initializer - ), - /*location*/ moveRangeEnd(initializer, -1) - ) - ); - } - } - else { - // Initializer is an expression. Emit the expression in the body, so that it's - // evaluated on every iteration. - const assignment = createAssignment(initializer, createElementAccess(rhsReference, counter)); - if (isDestructuringAssignment(assignment)) { - // This is a destructuring pattern, so we flatten the destructuring instead. - statements.push( - createStatement( - flattenDestructuringAssignment( - context, - assignment, - /*needsValue*/ false, - hoistVariableDeclaration, - visitor - ) - ) - ); - } - else { - // Currently there is not way to check that assignment is binary expression of destructing assignment - // so we have to cast never type to binaryExpression - (assignment).end = initializer.end; - statements.push(createStatement(assignment, /*location*/ moveRangeEnd(initializer, -1))); - } - } - - let bodyLocation: TextRange; - let statementsLocation: TextRange; - if (convertedLoopBodyStatements) { - addRange(statements, convertedLoopBodyStatements); - } - else { - const statement = visitNode(node.statement, visitor, isStatement); - if (isBlock(statement)) { - addRange(statements, statement.statements); - bodyLocation = statement; - statementsLocation = statement.statements; - } - else { - statements.push(statement); - } - } - - // The old emitter does not emit source maps for the expression - setEmitFlags(expression, EmitFlags.NoSourceMap | getEmitFlags(expression)); - - // The old emitter does not emit source maps for the block. - // We add the location to preserve comments. - const body = createBlock( - createNodeArray(statements, /*location*/ statementsLocation), - /*location*/ bodyLocation - ); - - setEmitFlags(body, EmitFlags.NoSourceMap | EmitFlags.NoTokenSourceMaps); - - const forStatement = createFor( - setEmitFlags( - createVariableDeclarationList([ - createVariableDeclaration(counter, /*type*/ undefined, createLiteral(0), /*location*/ moveRangePos(node.expression, -1)), - createVariableDeclaration(rhsReference, /*type*/ undefined, expression, /*location*/ node.expression) - ], /*location*/ node.expression), - EmitFlags.NoHoisting - ), - createLessThan( - counter, - createPropertyAccess(rhsReference, "length"), - /*location*/ node.expression - ), - createPostfixIncrement(counter, /*location*/ node.expression), - body, - /*location*/ node - ); - - // Disable trailing source maps for the OpenParenToken to align source map emit with the old emitter. - setEmitFlags(forStatement, EmitFlags.NoTokenTrailingSourceMaps); - return forStatement; + return convertForOf(node, convertedLoopBodyStatements, visitor, enableSubstitutionsForBlockScopedBindings, context, /*transformRest*/ false); } /** diff --git a/src/compiler/transformers/esnext.ts b/src/compiler/transformers/esnext.ts index a85098f03b6..26864a123ea 100644 --- a/src/compiler/transformers/esnext.ts +++ b/src/compiler/transformers/esnext.ts @@ -162,92 +162,7 @@ namespace ts { return visitEachChild(node, visitor, context); } - const expression = visitNode(node.expression, visitor, isExpression); - const statements: Statement[] = []; - const rhsReference = createTempVariable(/*recordTempVariable*/ undefined); - - // var { x, y } = _a, rest = __rest(_a, ["x", "y"]); - if (isVariableDeclarationList(initializer)) { - // This works whether the declaration is a var, let, or const. - // It will use rhsReference _a as the initializer. - const declarations = flattenVariableDestructuring( - initializer.declarations[0], - rhsReference, - visitor, - /*recordTempVariable*/ undefined, - /*transformRest*/ true, - ); - - const declarationList = createVariableDeclarationList(declarations, /*location*/ initializer); - setOriginalNode(declarationList, initializer); - - // Adjust the source map range for the first declaration to align with the old - // emitter. - const firstDeclaration = declarations[0]; - const lastDeclaration = lastOrUndefined(declarations); - setSourceMapRange(declarationList, createRange(firstDeclaration.pos, lastDeclaration.end)); - - statements.push( - createVariableStatement( - /*modifiers*/ undefined, - declarationList - ) - ); - } - else { - // Initializer is an object literal destructuring assignment. - // Emit the flattened assignments from the object literal expression in the body - const assignment = createAssignment(initializer, rhsReference); - statements.push( - createStatement( - flattenDestructuringAssignment( - context, - assignment, - /*needsValue*/ false, - hoistVariableDeclaration, - visitor, - /*transformRest*/ true - ) - ) - ); - } - - let bodyLocation: TextRange; - let statementsLocation: TextRange; - const statement = visitNode(node.statement, visitor, isStatement); - if (isBlock(statement)) { - addRange(statements, statement.statements); - bodyLocation = statement; - statementsLocation = statement.statements; - } - else { - statements.push(statement); - } - - // The old emitter does not emit source maps for the expression - setEmitFlags(expression, EmitFlags.NoSourceMap | getEmitFlags(expression)); - - // The old emitter does not emit source maps for the block. - // We add the location to preserve comments. - const body = createBlock( - createNodeArray(statements, /*location*/ statementsLocation), - /*location*/ bodyLocation - ); - - setEmitFlags(body, EmitFlags.NoSourceMap | EmitFlags.NoTokenSourceMaps); - - const forStatement = createForOf( - createVariableDeclarationList([ - createVariableDeclaration(rhsReference, /*type*/ undefined, /*initializer*/ undefined, /*location*/ node.expression) - ], /*location*/ node.expression), - node.expression, - body, - /*location*/ node - ); - - // Disable trailing source maps for the OpenParenToken to align source map emit with the old emitter. - setEmitFlags(forStatement, EmitFlags.NoTokenTrailingSourceMaps); - return forStatement; + return convertForOf(node, undefined, visitor, noop, context, /*transformRest*/ true); } function isRestBindingPattern(initializer: ForInitializer) {