@suchipi/traverse/dist/index.js

Basic depth-first traversal function

"use strict";
const stop = Symbol("stop");
function isNonPrimitive(value) {
    return ((typeof value === "object" && value != null) || typeof value === "function");
}
function doTraverse(obj, descriptor, filter, beforeCallback, afterCallback, path, seens) {
    if (seens.has(obj)) {
        return;
    }
    if (isNonPrimitive(obj)) {
        seens.add(obj);
    }
    if (beforeCallback) {
        const result = beforeCallback(obj, path, descriptor);
        if (result === stop) {
            return;
        }
    }
    if (Array.isArray(obj)) {
        const children = Array.from(obj);
        for (let i = 0; i < children.length; i++) {
            const childPath = path.concat(i);
            const childDescriptor = Object.getOwnPropertyDescriptor(obj, i);
            if (filter(childDescriptor, childPath)) {
                const child = children[i];
                doTraverse(child, childDescriptor, filter, beforeCallback, afterCallback, childPath, seens);
            }
        }
    }
    else if (isNonPrimitive(obj)) {
        const descriptors = Object.getOwnPropertyDescriptors(obj);
        const keys = Object.keys(descriptors);
        for (const key of keys) {
            const childPath = path.concat(key);
            const childDescriptor = descriptors[key];
            if (filter(childDescriptor, childPath)) {
                const value = obj[key];
                doTraverse(value, childDescriptor, filter, beforeCallback, afterCallback, childPath, seens);
            }
        }
    }
    if (afterCallback) {
        afterCallback(obj, path, descriptor);
    }
}
const defaultFilter = (descriptor, _path) => !descriptor.get;
function traverse(
/**
 * The tree structure to traverse.
 */
tree, 
/**
 * Callbacks to call during traversal
 */
callbacks) {
    const { before, after, filter = defaultFilter } = callbacks ?? {};
    const syntheticRootDescriptor = {
        value: tree,
        writable: true,
        enumerable: true,
        configurable: true,
    };
    if (!filter(syntheticRootDescriptor, [])) {
        return;
    }
    const setConstructor = typeof WeakSet === "undefined" ? Set : WeakSet;
    doTraverse(tree, syntheticRootDescriptor, filter, before, after, [], new setConstructor());
}
traverse.stop = stop;
traverse.default = traverse;
module.exports = traverse;