mahler/build/view.js

A automated task composer and HTN based planner for building autonomous system agents

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.View = void 0;
const is_array_index_1 = require("./is-array-index");
const path_1 = require("./path");
const pointer_1 = require("./pointer");
/**
 * Returns a view builder function from a given path
 */
function createView(ref, path) {
    const parts = path_1.Path.split(path);
    // Save the last element of the path so we can delete it
    const last = parts.pop();
    const obj = ref._;
    let parent = obj;
    for (const p of parts) {
        if (!Array.isArray(parent) && typeof parent !== 'object') {
            throw new pointer_1.InvalidPointer(path, obj);
        }
        if (Array.isArray(parent) && !(0, is_array_index_1.isArrayIndex)(p)) {
            throw new pointer_1.InvalidPointer(path, obj);
        }
        if (!(p in parent)) {
            // Cannot create a view if the path does not exist
            throw new pointer_1.InvalidPointer(path, obj);
        }
        parent = parent[p];
    }
    let pointer = parent;
    if (last != null) {
        if (!Array.isArray(parent) && typeof parent !== 'object') {
            throw new pointer_1.InvalidPointer(path, obj);
        }
        if (Array.isArray(parent) && !(0, is_array_index_1.isArrayIndex)(last)) {
            throw new pointer_1.InvalidPointer(path, obj);
        }
        pointer = parent[last];
    }
    const view = {
        _: pointer,
        delete() {
            if (last != null) {
                if (Array.isArray(parent)) {
                    parent.splice(+last, 1);
                }
                else {
                    delete parent[last];
                }
            }
        },
    };
    function update() {
        if (last != null) {
            if (Array.isArray(parent)) {
                parent.splice(+last, 1, view._);
            }
            else {
                parent[last] = view._;
            }
        }
        else {
            ref._ = view._;
        }
    }
    // We return a proxy so changes to the view._ value change
    // the parent's value
    return new Proxy(view, {
        set(target, prop, value) {
            const res = Reflect.set(target, prop, value);
            if (res) {
                update();
            }
            return res;
        },
    });
}
exports.View = {
    from: createView,
};
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