import {ContextualKeyword} from "../parser/tokenizer/keywords"; import {TokenType as tt} from "../parser/tokenizer/types"; /** * Get information about the class fields for this class, given a token processor pointing to the * open-brace at the start of the class. */ export default function getClassInfo( rootTransformer, tokens, nameManager, disableESTransforms, ) { const snapshot = tokens.snapshot(); const headerInfo = processClassHeader(tokens); let constructorInitializerStatements = []; const instanceInitializerNames = []; const staticInitializerNames = []; let constructorInsertPos = null; const fields = []; const rangesToRemove = []; const classContextId = tokens.currentToken().contextId; if (classContextId == null) { throw new Error("Expected non-null class context ID on class open-brace."); } tokens.nextToken(); while (!tokens.matchesContextIdAndLabel(tt.braceR, classContextId)) { if (tokens.matchesContextual(ContextualKeyword._constructor) && !tokens.currentToken().isType) { ({constructorInitializerStatements, constructorInsertPos} = processConstructor(tokens)); } else if (tokens.matches1(tt.semi)) { if (!disableESTransforms) { rangesToRemove.push({start: tokens.currentIndex(), end: tokens.currentIndex() + 1}); } tokens.nextToken(); } else if (tokens.currentToken().isType) { tokens.nextToken(); } else { // Either a method or a field. Skip to the identifier part. const statementStartIndex = tokens.currentIndex(); let isStatic = false; let isESPrivate = false; let isDeclareOrAbstract = false; while (isAccessModifier(tokens.currentToken())) { if (tokens.matches1(tt._static)) { isStatic = true; } if (tokens.matches1(tt.hash)) { isESPrivate = true; } if (tokens.matches1(tt._declare) || tokens.matches1(tt._abstract)) { isDeclareOrAbstract = true; } tokens.nextToken(); } if (isStatic && tokens.matches1(tt.braceL)) { // This is a static block, so don't process it in any special way. skipToNextClassElement(tokens, classContextId); continue; } if (isESPrivate) { // Sucrase doesn't attempt to transpile private fields; just leave them as-is. skipToNextClassElement(tokens, classContextId); continue; } if ( tokens.matchesContextual(ContextualKeyword._constructor) && !tokens.currentToken().isType ) { ({constructorInitializerStatements, constructorInsertPos} = processConstructor(tokens)); continue; } const nameStartIndex = tokens.currentIndex(); skipFieldName(tokens); if (tokens.matches1(tt.lessThan) || tokens.matches1(tt.parenL)) { // This is a method, so nothing to process. skipToNextClassElement(tokens, classContextId); continue; } // There might be a type annotation that we need to skip. while (tokens.currentToken().isType) { tokens.nextToken(); } if (tokens.matches1(tt.eq)) { const equalsIndex = tokens.currentIndex(); // This is an initializer, so we need to wrap in an initializer method. const valueEnd = tokens.currentToken().rhsEndIndex; if (valueEnd == null) { throw new Error("Expected rhsEndIndex on class field assignment."); } tokens.nextToken(); while (tokens.currentIndex() < valueEnd) { rootTransformer.processToken(); } let initializerName; if (isStatic) { initializerName = nameManager.claimFreeName("__initStatic"); staticInitializerNames.push(initializerName); } else { initializerName = nameManager.claimFreeName("__init"); instanceInitializerNames.push(initializerName); } // Fields start at the name, so `static x = 1;` has a field range of `x = 1;`. fields.push({ initializerName, equalsIndex, start: nameStartIndex, end: tokens.currentIndex(), }); } else if (!disableESTransforms || isDeclareOrAbstract) { // This is a regular field declaration, like `x;`. With the class transform enabled, we just // remove the line so that no output is produced. With the class transform disabled, we // usually want to preserve the declaration (but still strip types), but if the `declare` // or `abstract` keyword is specified, we should remove the line to avoid initializing the // value to undefined. rangesToRemove.push({start: statementStartIndex, end: tokens.currentIndex()}); } } } tokens.restoreToSnapshot(snapshot); if (disableESTransforms) { // With ES transforms disabled, we don't want to transform regular class // field declarations, and we don't need to do any additional tricks to // reference the constructor for static init, but we still need to transform // TypeScript field initializers defined as constructor parameters and we // still need to remove `declare` fields. For now, we run the same code // path but omit any field information, as if the class had no field // declarations. In the future, when we fully drop the class fields // transform, we can simplify this code significantly. return { headerInfo, constructorInitializerStatements, instanceInitializerNames: [], staticInitializerNames: [], constructorInsertPos, fields: [], rangesToRemove, }; } else { return { headerInfo, constructorInitializerStatements, instanceInitializerNames, staticInitializerNames, constructorInsertPos, fields, rangesToRemove, }; } } /** * Move the token processor to the next method/field in the class. * * To do that, we seek forward to the next start of a class name (either an open * bracket or an identifier, or the closing curly brace), then seek backward to * include any access modifiers. */ function skipToNextClassElement(tokens, classContextId) { tokens.nextToken(); while (tokens.currentToken().contextId !== classContextId) { tokens.nextToken(); } while (isAccessModifier(tokens.tokenAtRelativeIndex(-1))) { tokens.previousToken(); } } function processClassHeader(tokens) { const classToken = tokens.currentToken(); const contextId = classToken.contextId; if (contextId == null) { throw new Error("Expected context ID on class token."); } const isExpression = classToken.isExpression; if (isExpression == null) { throw new Error("Expected isExpression on class token."); } let className = null; let hasSuperclass = false; tokens.nextToken(); if (tokens.matches1(tt.name)) { className = tokens.identifierName(); } while (!tokens.matchesContextIdAndLabel(tt.braceL, contextId)) { // If this has a superclass, there will always be an `extends` token. If it doesn't have a // superclass, only type parameters and `implements` clauses can show up here, all of which // consist only of type tokens. A declaration like `class A {` should *not* count // as having a superclass. if (tokens.matches1(tt._extends) && !tokens.currentToken().isType) { hasSuperclass = true; } tokens.nextToken(); } return {isExpression, className, hasSuperclass}; } /** * Extract useful information out of a constructor, starting at the "constructor" name. */ function processConstructor(tokens) { const constructorInitializerStatements = []; tokens.nextToken(); const constructorContextId = tokens.currentToken().contextId; if (constructorContextId == null) { throw new Error("Expected context ID on open-paren starting constructor params."); } // Advance through parameters looking for access modifiers. while (!tokens.matchesContextIdAndLabel(tt.parenR, constructorContextId)) { if (tokens.currentToken().contextId === constructorContextId) { // Current token is an open paren or comma just before a param, so check // that param for access modifiers. tokens.nextToken(); if (isAccessModifier(tokens.currentToken())) { tokens.nextToken(); while (isAccessModifier(tokens.currentToken())) { tokens.nextToken(); } const token = tokens.currentToken(); if (token.type !== tt.name) { throw new Error("Expected identifier after access modifiers in constructor arg."); } const name = tokens.identifierNameForToken(token); constructorInitializerStatements.push(`this.${name} = ${name}`); } } else { tokens.nextToken(); } } // ) tokens.nextToken(); let constructorInsertPos = tokens.currentIndex(); // Advance through body looking for a super call. let foundSuperCall = false; while (!tokens.matchesContextIdAndLabel(tt.braceR, constructorContextId)) { if (!foundSuperCall && tokens.matches2(tt._super, tt.parenL)) { tokens.nextToken(); const superCallContextId = tokens.currentToken().contextId; if (superCallContextId == null) { throw new Error("Expected a context ID on the super call"); } while (!tokens.matchesContextIdAndLabel(tt.parenR, superCallContextId)) { tokens.nextToken(); } constructorInsertPos = tokens.currentIndex(); foundSuperCall = true; } tokens.nextToken(); } // } tokens.nextToken(); return {constructorInitializerStatements, constructorInsertPos}; } /** * Determine if this is any token that can go before the name in a method/field. */ function isAccessModifier(token) { return [ tt._async, tt._get, tt._set, tt.plus, tt.minus, tt._readonly, tt._static, tt._public, tt._private, tt._protected, tt._override, tt._abstract, tt.star, tt._declare, tt.hash, ].includes(token.type); } /** * The next token or set of tokens is either an identifier or an expression in square brackets, for * a method or field name. */ function skipFieldName(tokens) { if (tokens.matches1(tt.bracketL)) { const startToken = tokens.currentToken(); const classContextId = startToken.contextId; if (classContextId == null) { throw new Error("Expected class context ID on computed name open bracket."); } while (!tokens.matchesContextIdAndLabel(tt.bracketR, classContextId)) { tokens.nextToken(); } tokens.nextToken(); } else { tokens.nextToken(); } }