120 lines
3.5 KiB
JavaScript
120 lines
3.5 KiB
JavaScript
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/**
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* Copyright (c) Meta Platforms, Inc. and affiliates.
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*
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* This source code is licensed under the MIT license found in the
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* LICENSE file in the root directory of this source tree.
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*
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*
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* @format
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*/
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'use strict';
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Object.defineProperty(exports, "__esModule", {
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value: true
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});
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exports.SimpleTransform = void 0;
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var _SimpleTraverser = require("../traverse/SimpleTraverser");
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var _astNodeMutationHelpers = require("./astNodeMutationHelpers");
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function setParentPointer(node, parent) {
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if (parent != null) {
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// $FlowExpectedError[cannot-write]
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node.parent = parent;
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}
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}
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/**
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* A simple class to recursively tranform AST trees.
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*/
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class SimpleTransform {
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/**
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* Transform the given AST tree.
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* @param rootNode The root node to traverse.
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* @param options The option object.
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* @return The modified rootNode or a new node if the rootNode was transformed directly.
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*/
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transform(rootNode, options) {
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let resultRootNode = rootNode;
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_SimpleTraverser.SimpleTraverser.traverse(rootNode, {
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enter: (node, parent) => {
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// Ensure the parent pointers are correctly set before entering the node.
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setParentPointer(node, parent);
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const resultNode = options.transform(node);
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if (resultNode !== node) {
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let traversedResultNode = null;
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if (resultNode != null) {
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// Ensure the new node has the correct parent pointers before recursing again.
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setParentPointer(resultNode, parent);
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traversedResultNode = this.transform(resultNode, options);
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}
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if (parent == null) {
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if (node !== rootNode) {
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throw new Error('SimpleTransform infra error: Parent not set on non root node, this should not be possible');
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}
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resultRootNode = traversedResultNode;
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} else if (traversedResultNode == null) {
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(0, _astNodeMutationHelpers.removeNodeOnParent)(node, parent, options.visitorKeys);
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} else {
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(0, _astNodeMutationHelpers.replaceNodeOnParent)(node, parent, traversedResultNode, options.visitorKeys);
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setParentPointer(traversedResultNode, parent);
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}
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throw _SimpleTraverser.SimpleTraverser.Skip;
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}
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},
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leave(_node) {},
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visitorKeys: options.visitorKeys
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});
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return resultRootNode;
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}
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/**
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* Transform the given AST tree.
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* @param node The root node to traverse.
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* @param options The option object.
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*/
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static transform(node, options) {
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return new SimpleTransform().transform(node, options);
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}
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static transformProgram(program, options) {
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const result = SimpleTransform.transform(program, options);
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if ((result == null ? void 0 : result.type) === 'Program') {
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return result;
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}
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throw new Error('SimpleTransform.transformProgram: Expected program node.');
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}
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/**
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* Return a new AST node with the given properties overrided if needed.
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*
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* This function takes care to only create new nodes when needed. Referential equality of nodes
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* is important as its used to know if a node should be re-traversed.
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*
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* @param node The base AST node.
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* @param overrideProps New properties to apply to the node.
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* @return Either the orginal node if the properties matched the existing node or a new node with
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* the new properties.
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*/
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static nodeWith(node, overrideProps, visitorKeys) {
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return (0, _astNodeMutationHelpers.nodeWith)(node, overrideProps, visitorKeys);
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}
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}
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exports.SimpleTransform = SimpleTransform;
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