利用具有指定屬性的符號-PHP中文網路問答

如下所示的程式碼中，我定義了一些常數。我想使用Symbol來確保每個常數都是唯一的。但是當我使用以下程式碼行時：

if (isBtnDigitizePolygonClicked.value == true) {
    return polygDigiConstants.CONST_STRING_DIGITIZE;
}

上述程式碼回傳的值是Symbol('Digitize')，但我期望它是Digitize，如本教學所述：https://www. scaler.com/topics/enum-in-javascript/

#教學內容：

const Direction = Object.freeze({
  North: Symbol('north'),
  East: Symbol('east'),
  West: Symbol('west'),
  South: Symbol('south'),
})

const Pole = Object.freeze({
  North: Symbol('north'),
  South: Symbol('south'),
})

console.log(Direction.North === Pole.North)

上述代码的输出为：

false

請告訴我如何正確使用Symbol來定義屬性。

polygDigiConstants.js

function define(name, value) {
Object.defineProperty(polygDigiConstants, name, {
    value: value,
    enumerable: true,
    writable: false,
});
}

export let polygDigiConstants = {};

define('CONST_STRING_DIGITIZE', Symbol('Digitize'));
define('CONST_STRING_STOP_DIGITIZE', Symbol('Stop'));
define('CONST_STRING_CLEAR_DIGITIZED', Symbol('Clear'));

import { polygDigiConstants } from './polygDigiConstants.js'; if (isBtnDigitizePolygonClicked.value == true) { return polygDigiConstants.CONST_STRING_DIGITIZE.description; // 这将给你 'Digitize' } function define(name, value) { Object.defineProperty(polygDigiConstants, name, { value: value, enumerable: true, writable: false, }); } export let polygDigiConstants = {}; define('CONST_STRING_DIGITIZE', 'Digitize'); define('CONST_STRING_STOP_DIGITIZE', 'Stop'); define('CONST_STRING_CLEAR_DIGITIZED', 'Clear');