在 TypeScript 中是否有任何定义的 HashTable 类，如 C#

Question

I am developing web project using TypeScript. Here i need HashTable functionality in typescript like C# HashTable . But i have already developed that in JavaScript .

        this.length = 0;
    this.items = [];
    this.add = function (key, value) {
        this.previous = undefined;
        if (this.containsKey(key)) {
            this.previous = this.items[key];
        } else {
            this.length++;
        }
        this.items[key] = value;
        return this.previous;
    };
    this.clear = function () {
        this.items = {};
        this.length = 0;
    };
    this.contains = function (key) {
        return this.items.hasOwnProperty(key);
    };
    this.containsKey = function (key) {
        return this.items.hasOwnProperty(key);
    };
    this.containsValue = function (key) {
        return (this.items.hasOwnProperty(key) && this.items[key] != undefined) ? true : false;
    };
    this.getItem = function (key) {
        if (this.containsKey(key))
        {

            return this.items[key]
        }
        else
        {
            return  undefined;
        }
    };
    this.keys = function () {
        var keys = [];
        for (var k in this.items) {
            if (this.containsKey(k)) {
                keys.push(k);
            }
        }
        return keys;
    };
    this.remove = function (key) {
        if (this.containsKey(key)) {
            this.previous = this.items[key];
            this.length--;
            delete this.items[key];
            return this.previous;
        } else {
            return undefined;
        }
    };
    this.values = function () {
        var values = [];
        for (var k in this.items) {
            if (this.containsKey(k)) {
                values.push(this.items[k]);
            }
        }
        return values;
    };
    this.each = function (fn) {
        for (var k in this.items) {
            if (this.containsKey(k)) {
                fn(k, this.items[k]);
            }
        }
    };
    var previous = undefined;
}
return HashTable;

Like this, Typescript having predefined code? or i need to rewrite these codes from JS to TS? is there any simple property or class for this HashTable in typescript?

Or any other properties in TS to do the same HashTable functionality?

Answer 1

Modern JavaScript has three options:

• Map , is closest to HashTable to my knowlage. It main advantage is that it's keys may be of type Object .
• Set , it is basically an unique array.
• Object also known an {} . Key value store.

I would suggest to use object, but if your keys need to be object, use the Map .

---

JavaScript Object , or {} , is about 20x faster than Map . So use Map only if you need to use objects as keys.

Answer 2

Map is probably the right answer as suggested above, but maybe a hashmap with types looks something like this would work:

{ [key: string]: Type; }

or

{ [key: number]: Type; }