Add ObjectPropertyAccessor
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toasted-nutbread
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244
ext/mixed/js/object-property-accessor.js
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244
ext/mixed/js/object-property-accessor.js
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/*
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* Copyright (C) 2016-2020 Alex Yatskov <alex@foosoft.net>
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* Author: Alex Yatskov <alex@foosoft.net>
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <https://www.gnu.org/licenses/>.
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*/
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/**
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* Class used to get and set generic properties of an object by using path strings.
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*/
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class ObjectPropertyAccessor {
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constructor(target, setter=null) {
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this._target = target;
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this._setter = (typeof setter === 'function' ? setter : null);
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}
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getProperty(pathArray, pathLength) {
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let target = this._target;
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const ii = typeof pathLength === 'number' ? Math.min(pathArray.length, pathLength) : pathArray.length;
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for (let i = 0; i < ii; ++i) {
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const key = pathArray[i];
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if (!ObjectPropertyAccessor.hasProperty(target, key)) {
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throw new Error(`Invalid path: ${this.getPathString(pathArray.slice(0, i + 1))}`);
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}
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target = target[key];
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}
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return target;
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}
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setProperty(pathArray, value) {
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if (pathArray.length === 0) {
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throw new Error('Invalid path');
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}
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const target = this.getProperty(pathArray, pathArray.length - 1);
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const key = pathArray[pathArray.length - 1];
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if (!ObjectPropertyAccessor.isValidPropertyType(target, key)) {
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throw new Error(`Invalid path: ${this.getPathString(pathArray)}`);
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}
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if (this._setter !== null) {
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this._setter(target, key, value, pathArray);
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} else {
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target[key] = value;
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}
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}
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static getPathString(pathArray) {
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const regexShort = /^[a-zA-Z_][a-zA-Z0-9_]*$/;
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let pathString = '';
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let first = true;
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for (let part of pathArray) {
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switch (typeof part) {
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case 'number':
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if (Math.floor(part) !== part || part < 0) {
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throw new Error('Invalid index');
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}
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part = `[${part}]`;
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break;
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case 'string':
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if (!regexShort.test(part)) {
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const escapedPart = part.replace(/["\\]/g, '\\$&');
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part = `["${escapedPart}"]`;
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} else {
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if (!first) {
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part = `.${part}`;
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}
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}
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break;
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default:
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throw new Error(`Invalid type: ${typeof part}`);
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}
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pathString += part;
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first = false;
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}
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return pathString;
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}
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static getPathArray(pathString) {
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const pathArray = [];
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let state = 0;
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let quote = 0;
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let value = '';
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let escaped = false;
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for (const c of pathString) {
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const v = c.codePointAt(0);
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switch (state) {
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case 0: // Empty
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case 1: // Expecting identifier start
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if (v === 0x5b) { // '['
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if (state === 1) {
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throw new Error(`Unexpected character: ${c}`);
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}
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state = 3;
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} else if (
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(v >= 0x41 && v <= 0x5a) || // ['A', 'Z']
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(v >= 0x61 && v <= 0x7a) || // ['a', 'z']
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v === 0x5f // '_'
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) {
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state = 2;
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value += c;
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} else {
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throw new Error(`Unexpected character: ${c}`);
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}
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break;
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case 2: // Identifier
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if (
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(v >= 0x41 && v <= 0x5a) || // ['A', 'Z']
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(v >= 0x61 && v <= 0x7a) || // ['a', 'z']
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(v >= 0x30 && v <= 0x39) || // ['0', '9']
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v === 0x5f // '_'
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) {
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value += c;
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} else if (v === 0x5b) { // '['
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pathArray.push(value);
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value = '';
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state = 3;
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} else if (v === 0x2e) { // '.'
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pathArray.push(value);
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value = '';
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state = 1;
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} else {
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throw new Error(`Unexpected character: ${c}`);
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}
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break;
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case 3: // Open bracket
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if (v === 0x22 || v === 0x27) { // '"' or '\''
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quote = v;
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state = 4;
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} else if (v >= 0x30 && v <= 0x39) { // ['0', '9']
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state = 5;
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value += c;
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} else {
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throw new Error(`Unexpected character: ${c}`);
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}
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break;
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case 4: // Quoted string
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if (escaped) {
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value += c;
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escaped = false;
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} else if (v === 0x5c) { // '\\'
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escaped = true;
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} else if (v !== quote) {
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value += c;
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} else {
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state = 6;
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}
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break;
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case 5: // Number
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if (v >= 0x30 && v <= 0x39) { // ['0', '9']
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value += c;
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} else if (v === 0x5d) { // ']'
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pathArray.push(Number.parseInt(value, 10));
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value = '';
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state = 7;
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} else {
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throw new Error(`Unexpected character: ${c}`);
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}
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break;
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case 6: // Expecting closing bracket after quoted string
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if (v === 0x5d) { // ']'
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pathArray.push(value);
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value = '';
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state = 7;
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} else {
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throw new Error(`Unexpected character: ${c}`);
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}
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break;
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case 7: // Expecting . or [
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if (v === 0x5b) { // '['
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state = 3;
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} else if (v === 0x2e) { // '.'
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state = 1;
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} else {
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throw new Error(`Unexpected character: ${c}`);
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}
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break;
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}
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}
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switch (state) {
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case 0:
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case 7:
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break;
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case 2:
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pathArray.push(value);
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value = '';
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break;
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default:
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throw new Error('Path not terminated correctly');
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}
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return pathArray;
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}
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static hasProperty(object, property) {
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switch (typeof property) {
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case 'string':
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return (
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typeof object === 'object' &&
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object !== null &&
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!Array.isArray(object) &&
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Object.prototype.hasOwnProperty.call(object, property)
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);
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case 'number':
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return (
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Array.isArray(object) &&
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property >= 0 &&
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property < object.length &&
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property === Math.floor(property)
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);
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default:
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return false;
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}
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}
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static isValidPropertyType(object, property) {
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switch (typeof property) {
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case 'string':
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return (
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typeof object === 'object' &&
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object !== null &&
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!Array.isArray(object)
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);
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case 'number':
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return (
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Array.isArray(object) &&
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property >= 0 &&
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property === Math.floor(property)
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);
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default:
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return false;
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}
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}
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}
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