estree.js

// @flow

import { type TokenType } from "../tokenizer/types";
import type Parser from "../parser";
import type { ExpressionErrors } from "../parser/util";
import * as N from "../types";
import type { Node as NodeType, NodeBase, File } from "../types";
import type { Position } from "../util/location";
import { Errors } from "../parse-error";

const { defineProperty } = Object;
const toUnenumerable = (object, key) =>
  defineProperty(object, key, { enumerable: false, value: object[key] });

function toESTreeLocation(node: any) {
  node.loc.start && toUnenumerable(node.loc.start, "index");
  node.loc.end && toUnenumerable(node.loc.end, "index");

  return node;
}

export default (superClass: Class<Parser>): Class<Parser> =>
  class extends superClass {
    parse(): File {
      const file = toESTreeLocation(super.parse());

      if (this.options.tokens) {
        file.tokens = file.tokens.map(toESTreeLocation);
      }

      return file;
    }

    parseRegExpLiteral({ pattern, flags }): N.Node {
      let regex = null;
      try {
        regex = new RegExp(pattern, flags);
      } catch (e) {
        // In environments that don't support these flags value will
        // be null as the regex can't be represented natively.
      }
      const node = this.estreeParseLiteral<N.EstreeRegExpLiteral>(regex);
      node.regex = { pattern, flags };

      return node;
    }

    parseBigIntLiteral(value: any): N.Node {
      // https://github.com/estree/estree/blob/master/es2020.md#bigintliteral
      let bigInt;
      try {
        // $FlowIgnore
        bigInt = BigInt(value);
      } catch {
        bigInt = null;
      }
      const node = this.estreeParseLiteral<N.EstreeBigIntLiteral>(bigInt);
      node.bigint = String(node.value || value);

      return node;
    }

    parseDecimalLiteral(value: any): N.Node {
      // https://github.com/estree/estree/blob/master/experimental/decimal.md
      // todo: use BigDecimal when node supports it.
      const decimal = null;
      const node = this.estreeParseLiteral(decimal);
      node.decimal = String(node.value || value);

      return node;
    }

    estreeParseLiteral<T: N.Node>(value: any) {
      return this.parseLiteral<T>(value, "Literal");
    }

    parseStringLiteral(value: any): N.Node {
      return this.estreeParseLiteral(value);
    }

    parseNumericLiteral(value: any): any {
      return this.estreeParseLiteral(value);
    }

    parseNullLiteral(): N.Node {
      return this.estreeParseLiteral(null);
    }

    parseBooleanLiteral(value: boolean): N.BooleanLiteral {
      return this.estreeParseLiteral(value);
    }

    directiveToStmt(directive: N.Directive): N.ExpressionStatement {
      const directiveLiteral = directive.value;

      const stmt = this.startNodeAt(directive.start, directive.loc.start);
      const expression = this.startNodeAt(
        directiveLiteral.start,
        directiveLiteral.loc.start,
      );

      expression.value = directiveLiteral.extra.expressionValue;
      expression.raw = directiveLiteral.extra.raw;

      stmt.expression = this.finishNodeAt(
        expression,
        "Literal",
        directiveLiteral.loc.end,
      );
      stmt.directive = directiveLiteral.extra.raw.slice(1, -1);

      return this.finishNodeAt(stmt, "ExpressionStatement", directive.loc.end);
    }

    // ==================================
    // Overrides
    // ==================================

    initFunction(
      node: N.BodilessFunctionOrMethodBase,
      isAsync: ?boolean,
    ): void {
      super.initFunction(node, isAsync);
      node.expression = false;
    }

    checkDeclaration(node: N.Pattern | N.ObjectProperty): void {
      if (node != null && this.isObjectProperty(node)) {
        this.checkDeclaration(((node: any): N.EstreeProperty).value);
      } else {
        super.checkDeclaration(node);
      }
    }

    getObjectOrClassMethodParams(method: N.ObjectMethod | N.ClassMethod) {
      return ((method: any): N.EstreeProperty | N.EstreeMethodDefinition).value
        .params;
    }

    isValidDirective(stmt: N.Statement): boolean {
      return (
        stmt.type === "ExpressionStatement" &&
        stmt.expression.type === "Literal" &&
        typeof stmt.expression.value === "string" &&
        !stmt.expression.extra?.parenthesized
      );
    }

    parseBlockBody(
      node: N.BlockStatementLike,
      ...args: [?boolean, boolean, TokenType, void | (boolean => void)]
    ): void {
      super.parseBlockBody(node, ...args);

      const directiveStatements = node.directives.map(d =>
        this.directiveToStmt(d),
      );
      node.body = directiveStatements.concat(node.body);
      // $FlowIgnore - directives isn't optional in the type definition
      delete node.directives;
    }

    pushClassMethod(
      classBody: N.ClassBody,
      method: N.ClassMethod,
      isGenerator: boolean,
      isAsync: boolean,
      isConstructor: boolean,
      allowsDirectSuper: boolean,
    ): void {
      this.parseMethod(
        method,
        isGenerator,
        isAsync,
        isConstructor,
        allowsDirectSuper,
        "ClassMethod",
        true,
      );
      if (method.typeParameters) {
        // $FlowIgnore
        method.value.typeParameters = method.typeParameters;
        delete method.typeParameters;
      }
      classBody.body.push(method);
    }

    parsePrivateName(): any {
      const node = super.parsePrivateName();
      if (!process.env.BABEL_8_BREAKING) {
        if (!this.getPluginOption("estree", "classFeatures")) {
          return node;
        }
      }
      return this.convertPrivateNameToPrivateIdentifier(node);
    }

    convertPrivateNameToPrivateIdentifier(
      node: N.PrivateName,
    ): N.EstreePrivateIdentifier {
      const name = super.getPrivateNameSV(node);
      node = (node: any);
      delete node.id;
      node.name = name;
      node.type = "PrivateIdentifier";
      return node;
    }

    isPrivateName(node: N.Node): boolean {
      if (!process.env.BABEL_8_BREAKING) {
        if (!this.getPluginOption("estree", "classFeatures")) {
          return super.isPrivateName(node);
        }
      }
      return node.type === "PrivateIdentifier";
    }

    getPrivateNameSV(node: N.Node): string {
      if (!process.env.BABEL_8_BREAKING) {
        if (!this.getPluginOption("estree", "classFeatures")) {
          return super.getPrivateNameSV(node);
        }
      }
      return node.name;
    }

    parseLiteral<T: N.Node>(value: any, type: $ElementType<T, "type">): T {
      const node = super.parseLiteral<T>(value, type);
      node.raw = node.extra.raw;
      delete node.extra;

      return node;
    }

    parseFunctionBody(
      node: N.Function,
      allowExpression: ?boolean,
      isMethod?: boolean = false,
    ): void {
      super.parseFunctionBody(node, allowExpression, isMethod);
      node.expression = node.body.type !== "BlockStatement";
    }

    parseMethod<T: N.MethodLike>(
      node: T,
      isGenerator: boolean,
      isAsync: boolean,
      isConstructor: boolean,
      allowDirectSuper: boolean,
      type: string,
      inClassScope: boolean = false,
    ): T {
      let funcNode = this.startNode();
      funcNode.kind = node.kind; // provide kind, so super method correctly sets state
      funcNode = super.parseMethod(
        funcNode,
        isGenerator,
        isAsync,
        isConstructor,
        allowDirectSuper,
        type,
        inClassScope,
      );
      funcNode.type = "FunctionExpression";
      delete funcNode.kind;
      // $FlowIgnore
      node.value = funcNode;
      if (type === "ClassPrivateMethod") {
        // $FlowIgnore
        node.computed = false;
      }
      type = "MethodDefinition";
      return this.finishNode(node, type);
    }

    parseClassProperty(...args: [N.ClassProperty]): any {
      const propertyNode = (super.parseClassProperty(...args): any);
      if (!process.env.BABEL_8_BREAKING) {
        if (!this.getPluginOption("estree", "classFeatures")) {
          return (propertyNode: N.EstreePropertyDefinition);
        }
      }
      propertyNode.type = "PropertyDefinition";
      return (propertyNode: N.EstreePropertyDefinition);
    }

    parseClassPrivateProperty(...args: [N.ClassPrivateProperty]): any {
      const propertyNode = (super.parseClassPrivateProperty(...args): any);
      if (!process.env.BABEL_8_BREAKING) {
        if (!this.getPluginOption("estree", "classFeatures")) {
          return (propertyNode: N.EstreePropertyDefinition);
        }
      }
      propertyNode.type = "PropertyDefinition";
      propertyNode.computed = false;
      return (propertyNode: N.EstreePropertyDefinition);
    }

    parseObjectMethod(
      prop: N.ObjectMethod,
      isGenerator: boolean,
      isAsync: boolean,
      isPattern: boolean,
      isAccessor: boolean,
    ): ?N.ObjectMethod {
      const node: N.EstreeProperty = (super.parseObjectMethod(
        prop,
        isGenerator,
        isAsync,
        isPattern,
        isAccessor,
      ): any);

      if (node) {
        node.type = "Property";
        if (((node: any): N.ClassMethod).kind === "method") node.kind = "init";
        node.shorthand = false;
      }

      return (node: any);
    }

    parseObjectProperty(
      prop: N.ObjectProperty,
      startPos: ?number,
      startLoc: ?Position,
      isPattern: boolean,
      refExpressionErrors: ?ExpressionErrors,
    ): ?N.ObjectProperty {
      const node: N.EstreeProperty = (super.parseObjectProperty(
        prop,
        startPos,
        startLoc,
        isPattern,
        refExpressionErrors,
      ): any);

      if (node) {
        node.kind = "init";
        node.type = "Property";
      }

      return (node: any);
    }

    isValidLVal(type: string, ...rest) {
      return type === "Property" ? "value" : super.isValidLVal(type, ...rest);
    }

    isAssignable(node: N.Node, isBinding?: boolean): boolean {
      if (node != null && this.isObjectProperty(node)) {
        return this.isAssignable(node.value, isBinding);
      }
      return super.isAssignable(node, isBinding);
    }

    toAssignable(node: N.Node, isLHS: boolean = false): void {
      if (node != null && this.isObjectProperty(node)) {
        const { key, value } = node;
        if (this.isPrivateName(key)) {
          this.classScope.usePrivateName(
            this.getPrivateNameSV(key),
            key.loc.start,
          );
        }
        this.toAssignable(value, isLHS);
      } else {
        super.toAssignable(node, isLHS);
      }
    }

    toAssignableObjectExpressionProp(prop: N.Node) {
      if (prop.kind === "get" || prop.kind === "set") {
        this.raise(Errors.PatternHasAccessor, { at: prop.key });
      } else if (prop.method) {
        this.raise(Errors.PatternHasMethod, { at: prop.key });
      } else {
        super.toAssignableObjectExpressionProp(...arguments);
      }
    }

    finishCallExpression<T: N.CallExpression | N.OptionalCallExpression>(
      node: T,
      optional: boolean,
    ): N.Expression {
      super.finishCallExpression(node, optional);

      if (node.callee.type === "Import") {
        ((node: N.Node): N.EstreeImportExpression).type = "ImportExpression";
        ((node: N.Node): N.EstreeImportExpression).source = node.arguments[0];
        if (this.hasPlugin("importAssertions")) {
          ((node: N.Node): N.EstreeImportExpression).attributes =
            node.arguments[1] ?? null;
        }
        // $FlowIgnore - arguments isn't optional in the type definition
        delete node.arguments;
        // $FlowIgnore - callee isn't optional in the type definition
        delete node.callee;
      }

      return node;
    }

    toReferencedArguments(
      node:
        | N.CallExpression
        | N.OptionalCallExpression
        | N.EstreeImportExpression,
      /* isParenthesizedExpr?: boolean, */
    ) {
      // ImportExpressions do not have an arguments array.
      if (node.type === "ImportExpression") {
        return;
      }

      super.toReferencedArguments(node);
    }

    parseExport(node: N.Node) {
      super.parseExport(node);

      switch (node.type) {
        case "ExportAllDeclaration":
          node.exported = null;
          break;

        case "ExportNamedDeclaration":
          if (
            node.specifiers.length === 1 &&
            node.specifiers[0].type === "ExportNamespaceSpecifier"
          ) {
            node.type = "ExportAllDeclaration";
            node.exported = node.specifiers[0].exported;
            delete node.specifiers;
          }

          break;
      }

      return node;
    }

    parseSubscript(
      base: N.Expression,
      startPos: number,
      startLoc: Position,
      noCalls: ?boolean,
      state: N.ParseSubscriptState,
    ) {
      const node = super.parseSubscript(
        base,
        startPos,
        startLoc,
        noCalls,
        state,
      );

      if (state.optionalChainMember) {
        // https://github.com/estree/estree/blob/master/es2020.md#chainexpression
        if (
          node.type === "OptionalMemberExpression" ||
          node.type === "OptionalCallExpression"
        ) {
          node.type = node.type.substring(8); // strip Optional prefix
        }
        if (state.stop) {
          const chain = this.startNodeAtNode(node);
          chain.expression = node;
          return this.finishNode(chain, "ChainExpression");
        }
      } else if (
        node.type === "MemberExpression" ||
        node.type === "CallExpression"
      ) {
        node.optional = false;
      }

      return node;
    }

    hasPropertyAsPrivateName(node: N.Node): boolean {
      if (node.type === "ChainExpression") {
        node = node.expression;
      }
      return super.hasPropertyAsPrivateName(node);
    }

    isOptionalChain(node: N.Node): boolean {
      return node.type === "ChainExpression";
    }

    isObjectProperty(node: N.Node): boolean {
      return node.type === "Property" && node.kind === "init" && !node.method;
    }

    isObjectMethod(node: N.Node): boolean {
      return node.method || node.kind === "get" || node.kind === "set";
    }

    finishNodeAt<T: NodeType>(node: T, type: string, endLoc: Position): T {
      return toESTreeLocation(super.finishNodeAt(node, type, endLoc));
    }

    resetStartLocation(node: N.Node, start: number, startLoc: Position) {
      super.resetStartLocation(node, start, startLoc);
      toESTreeLocation(node);
    }

    resetEndLocation(
      node: NodeBase,
      endLoc?: Position = this.state.lastTokEndLoc,
    ): void {
      super.resetEndLocation(node, endLoc);
      toESTreeLocation(node);
    }
  };