attrpath/dist/esm/handler.js

Attribute Path Traverser.

/**
 * Copyright © 2020 2021 2022 7thCode.(http://seventh-code.com/)
 * This software is released under the MIT License.
 * opensource.org/licenses/mit-license.php
 */
"use strict";
import { isContainer } from "./base";
import { TokenType } from "./parser";
/**
 * BaseHandler
 *
 * @remarks
 *
 */
export class BaseHandler {
}
/**
 * ValueHandler
 *
 * actually traverse the object.
 *
 * @remarks
 *
 */
export class ValueHandler extends BaseHandler {
    /**
     *
     * @remarks
     */
    constructor(root_value) {
        super();
        this.current_value = null;
        this.current_value = root_value;
    }
    /**
     * value
     *
     * Data
     */
    get value() {
        return this.current_value;
    }
    /**
     * Symbol Handler
     *
     * @remarks
     * Executed when Parser recognizes Token.
     *
     * @param type - Symbol Type
     * @param word
     * @param term
     * @returns void
     *
     */
    token(type, word, term) {
        switch (type) {
            case TokenType.operator:
                //           console.log("operator " + word);
                break;
            case TokenType.number:
                //            console.log("number " + word);
                break;
            case TokenType.index:
                this.current_value = ValueHandler.sibling(this.current_value, word);
                break;
            case TokenType.name:
                this.current_value = ValueHandler.child(this.current_value, word);
                break;
        }
    }
    /**
     * Sibling
     *
     * @remarks
     * Extract array elements from index
     *
     * @param array - Array
     * @param index - Index
     * @returns Array member
     *
     */
    static sibling(array, index) {
        let result = undefined;
        if (Array.isArray(array)) {
            result = array[Number(index)];
        }
        return result;
    }
    /**
     * child
     *
     * @remarks
     * Returns an object member.
     *
     * @param obj - Object
     * @param attr - Attribute Name
     * @returns Object member
     *
     */
    static child(obj, attr) {
        let result = undefined;
        if (isContainer(obj)) {
            if (attr in obj) {
                result = obj[attr];
            }
        }
        return result;
    }
}
/**
 * Updater
 *
 * It actually traverses and updates objects.
 *
 * @remarks
 *
 */
export class Updater extends ValueHandler {
    /**
     *
     * @remarks
     */
    constructor(root_value, new_value) {
        super(root_value);
        this.new_value = new_value;
    }
    /**
     * Symbol Handler
     *
     * @remarks
     * Executed when Parser recognizes Token.
     *
     * @param type - Symbol Type
     * @param word
     * @param term
     * @returns void
     *
     */
    token(type, word, term) {
        if (this.current_value) {
            switch (type) {
                case TokenType.index:
                    {
                        if (term) {
                            if (this.current_value.length > word) {
                                this.current_value[word] = this.new_value;
                            }
                        }
                        else {
                            this.current_value = Updater.sibling(this.current_value, word);
                        }
                    }
                    break;
                case TokenType.name:
                    {
                        if (term) {
                            this.current_value[word] = this.new_value;
                        }
                        else {
                            this.current_value = Updater.child(this.current_value, word);
                        }
                    }
                    break;
            }
        }
    }
}
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