source: frontend/node_modules/estree-walker/dist/estree-walker.umd.js

(function (global, factory) {
        typeof exports === 'object' && typeof module !== 'undefined' ? factory(exports) :
        typeof define === 'function' && define.amd ? define(['exports'], factory) :
        (factory((global.estreeWalker = {})));
}(this, (function (exports) { 'use strict';

        function walk(ast, { enter, leave }) {
                return visit(ast, null, enter, leave);
        }

        let should_skip = false;
        let should_remove = false;
        let replacement = null;
        const context = {
                skip: () => should_skip = true,
                remove: () => should_remove = true,
                replace: (node) => replacement = node
        };

        function replace(parent, prop, index, node) {
                if (parent) {
                        if (index !== null) {
                                parent[prop][index] = node;
                        } else {
                                parent[prop] = node;
                        }
                }
        }

        function remove(parent, prop, index) {
                if (parent) {
                        if (index !== null) {
                                parent[prop].splice(index, 1);
                        } else {
                                delete parent[prop];
                        }
                }
        }

        function visit(
                node,
                parent,
                enter,
                leave,
                prop,
                index
        ) {
                if (node) {
                        if (enter) {
                                const _should_skip = should_skip;
                                const _should_remove = should_remove;
                                const _replacement = replacement;
                                should_skip = false;
                                should_remove = false;
                                replacement = null;

                                enter.call(context, node, parent, prop, index);

                                if (replacement) {
                                        node = replacement;
                                        replace(parent, prop, index, node);
                                }

                                if (should_remove) {
                                        remove(parent, prop, index);
                                }

                                const skipped = should_skip;
                                const removed = should_remove;

                                should_skip = _should_skip;
                                should_remove = _should_remove;
                                replacement = _replacement;

                                if (skipped) return node;
                                if (removed) return null;
                        }

                        for (const key in node) {
                                const value = (node )[key];

                                if (typeof value !== 'object') {
                                        continue;
                                }

                                else if (Array.isArray(value)) {
                                        for (let j = 0, k = 0; j < value.length; j += 1, k += 1) {
                                                if (value[j] !== null && typeof value[j].type === 'string') {
                                                        if (!visit(value[j], node, enter, leave, key, k)) {
                                                                // removed
                                                                j--;
                                                        }
                                                }
                                        }
                                }

                                else if (value !== null && typeof value.type === 'string') {
                                        visit(value, node, enter, leave, key, null);
                                }
                        }

                        if (leave) {
                                const _replacement = replacement;
                                const _should_remove = should_remove;
                                replacement = null;
                                should_remove = false;

                                leave.call(context, node, parent, prop, index);

                                if (replacement) {
                                        node = replacement;
                                        replace(parent, prop, index, node);
                                }

                                if (should_remove) {
                                        remove(parent, prop, index);
                                }

                                const removed = should_remove;

                                replacement = _replacement;
                                should_remove = _should_remove;

                                if (removed) return null;
                        }
                }

                return node;
        }

        exports.walk = walk;

        Object.defineProperty(exports, '__esModule', { value: true });

})));