typescript TypeScript上的简单帮助程序模块，用于在浏览器中使用本地存储（HTML5）。还有类来存储需要的电子邮件列表

Posted 2021-05-21

// module with classes and logic for working with local storage in browsers via JavaScript
// see also: http://professorweb.ru/my/html/html5/level5/5_1.php
module StorageHelper {
    export interface IStorageItem {
        key: string;
        value: any;
    }

    export class StorageItem {
        key: string;
        value: any;

        constructor(data: IStorageItem) {
            this.key = data.key;
            this.value = data.value;
        }
    }

    // class for working with local storage in browser (common that can use other classes for store some data)
    export class LocalStorageWorker {
        localStorageSupported: boolean;

        constructor() {
            this.localStorageSupported = typeof window['localStorage'] != "undefined" && window['localStorage'] != null;
        }

        // add value to storage
        add(key: string, item: string) {
            if (this.localStorageSupported) {
                localStorage.setItem(key, item);
            }
        }

        // get all values from storage (all items)
        getAllItems(): Array<StorageItem> {
            var list = new Array<StorageItem>();

            for (var i = 0; i < localStorage.length; i++) {
                var key = localStorage.key(i);
                var value = localStorage.getItem(key);

                list.push(new StorageItem({
                    key: key,
                    value: value
                }));
            }

            return list;
        }

        // get only all values from localStorage
        getAllValues(): Array<any> {
            var list = new Array<any>();

            for (var i = 0; i < localStorage.length; i++) {
                var key = localStorage.key(i);
                var value = localStorage.getItem(key);

                list.push(value);
            }

            return list;
        }

        // get one item by key from storage
        get(key: string): string {
            if (this.localStorageSupported) {
                var item = localStorage.getItem(key);
                return item;
            } else {
                return null;
            }
        }

        // remove value from storage
        remove(key: string) {
            if (this.localStorageSupported) {
                localStorage.removeItem(key);
            }
        }

        // clear storage (remove all items from it)
        clear() {
            if (this.localStorageSupported) {
                localStorage.clear();
            }
        }
    }

    // custom class for store emails in local storage
    export class EmailStorage {
        storageWorker: LocalStorageWorker;

        // main key that use for store list of emails
        storageKey: string;

        // list of emails
        addresses: Array<string>;

        constructor(storageKey: string) {
            this.storageWorker = new LocalStorageWorker();

            this.storageKey = storageKey;

            this.addresses = new Array<string>();

            this.activate();
        }

        // activate custom storage for emails
        activate() {
            //this.clear();

            this.loadAll();
        }

        // load all emails from storage to list for working with it
        loadAll() {
            var storageData = this.storageWorker.get(this.storageKey);

            if (storageData != null && storageData.length > 0) {
                var emails = JSON.parse(storageData);
                console.log(emails);
                if (emails != null) {
                    this.addresses = emails;
                }
                console.log(this.addresses);
            }
        }

        // add new email (without duplicate)
        addEmail(email: string) {
            if (email.length > 0) {

                // 1. Split email addresses if needed (if we get list of emails)
                var mas = email.split(/,|;/g);
                //console.log(mas);

                // 2. Add each email in the splited list
                for (var i = 0; i < mas.length; i++) {
                    // check if not exist and not add new (duplicate)
                    var index = this.addresses.indexOf(mas[i].trim());
                    if (index < 0) {
                        this.addresses.push(mas[i].trim());
                    }
                }

                console.log(this.addresses);

                // 3. save to storage
                this.save();
            }
        }

        // clear all data about emails
        clear() {
            // remove data by key from storage
            this.storageWorker.add(this.storageKey, "");

            // or remove with key
            //this.storageWorker.remove(this.storageKey);
        }

        // save to storage (save as JSON string)
        save() {
            var jsonEmails = JSON.stringify(this.addresses);
            this.storageWorker.add(this.storageKey, jsonEmails);
        }
    }
}