來學習typescript 吧！ --7 內建物件

來學習typescript 吧！ --7 內建物件

JavaScript 中有很多內建物件，它們可以直接在 TypeScript 中當做定義好了的型別。

ECMAScript 的內建物件有：Array、Object、Function、Boolean、String

let b: Boolean = new Boolean(1);
let d: Date = new Date();
let err: Error = new Error('Error occurred');
let f: Function = function () { };
let n: Number = new Number(1);
let r: RegExp = new RegExp('/./');
let s: String = new String('str');

DOM 和 BOM 的內建物件

Document、HTMLElement、Event、NodeList 等

let body: HTMLElement = document.body;
let allDiv: NodeList = document.querySelectorAll('div');
​
//讀取div 這種需要型別斷言 或者加個判斷應為讀不到返回null
let div:HTMLElement = document.querySelector('div') as HTMLDivElement
​
document.addEventListener('click', function (e: MouseEvent) {
    // MouseEvent
})

interface HTMLElementTagNameMap {
    "a": HTMLAnchorElement;
    "abbr": HTMLElement;
    "address": HTMLElement;
    "applet":  HTMLAppletElement;
    "area": HTMLAreaElement;
    "article": HTMLElement;
    "aside": HTMLElement;
    "audio": HTMLAudioElement;
    "b": HTMLElement;
    "base": HTMLBaseElement;
    "bdi": HTMLElement;
    "bdo": HTMLElement;
    "blockquote": HTMLQuoteElement;
    "body": HTMLBodyElement;
    "br": HTMLBRElement;
    "button": HTMLButtonElement;
    "canvas": HTMLCanvasElement;
    "caption": HTMLTableCaptionElement;
    "cite": HTMLElement;
    "code": HTMLElement;
    "col": HTMLTableColElement;
    "colgroup": HTMLTableColElement;
    "data": HTMLDataElement;
    "datalist": HTMLDataListElement;
    "dd": HTMLElement;
    "del": HTMLModElement;
    "details": HTMLDetailsElement;
    "dfn": HTMLElement;
    "dialog": HTMLDialogElement;
    "dir": HTMLDirectoryElement;
    "div": HTMLDivElement;
    "dl": HTMLDListElement;
    "dt": HTMLElement;
    "em": HTMLElement;
    "embed": HTMLEmbedElement;
    "fieldset": HTMLFieldSetElement;
    "figcaption": HTMLElement;
    "figure": HTMLElement;
    "font": HTMLFontElement;
    "footer": HTMLElement;
    "form": HTMLFormElement;
    "frame": HTMLFrameElement;
    "frameset": HTMLFrameSetElement;
    "h1": HTMLHeadingElement;
    "h2": HTMLHeadingElement;
    "h3": HTMLHeadingElement;
    "h4": HTMLHeadingElement;
    "h5": HTMLHeadingElement;
    "h6": HTMLHeadingElement;
    "head": HTMLHeadElement;
    "header": HTMLElement;
    "hgroup": HTMLElement;
    "hr": HTMLHRElement;
    "html": HTMLHtmlElement;
    "i": HTMLElement;
    "iframe": HTMLIFrameElement;
    "img": HTMLImageElement;
    "input": HTMLInputElement;
    "ins": HTMLModElement;
    "kbd": HTMLElement;
    "label": HTMLLabelElement;
    "legend": HTMLLegendElement;
    "li": HTMLLIElement;
    "link": HTMLLinkElement;
    "main": HTMLElement;
    "map": HTMLMapElement;
    "mark": HTMLElement;
    "marquee": HTMLElement;
    "menu": HTMLMenuElement;
    "meta": HTMLMetaElement;
    "meter": HTMLMeterElement;
    "nav": HTMLElement;
    "noscript": HTMLElement;
    "object": HTMLObjectElement;
    "ol": HTMLOListElement;
    "optgroup": HTMLOptGroupElement;
    "option": HTMLOptionElement;
    "output": HTMLOutputElement;
    "p": HTMLParagraphElement;
    "param":  HTMLParamElement;
    "picture": HTMLPictureElement;
    "pre": HTMLPreElement;
    "progress": HTMLProgressElement;
    "q": HTMLQuoteElement;
    "rp": HTMLElement;
    "rt": HTMLElement;
    "ruby": HTMLElement;
    "s": HTMLElement;
    "samp": HTMLElement;
    "script": HTMLScriptElement;
    "section": HTMLElement;
    "select": HTMLSelectElement;
    "slot": HTMLSlotElement;
    "small": HTMLElement;
    "source": HTMLSourceElement;
    "span": HTMLSpanElement;
    "strong": HTMLElement;
    "style": HTMLStyleElement;
    "sub": HTMLElement;
    "summary": HTMLElement;
    "sup": HTMLElement;
    "table": HTMLTableElement;
    "tbody": HTMLTableSectionElement;
    "td":  HTMLTableCellElement;
    "template": HTMLTemplateElement;
    "textarea": HTMLTextAreaElement;
    "tfoot": HTMLTableSectionElement;
    "th":  HTMLTableCellElement;
    "thead": HTMLTableSectionElement;
    "time": HTMLTimeElement;
    "title": HTMLTitleElement;
    "tr": HTMLTableRowElement;
    "track": HTMLTrackElement;
    "u": HTMLElement;
    "ul": HTMLUListElement;
    "var": HTMLElement;
    "video": HTMLVideoElement;
    "wbr": HTMLElement;
}

常用

let  local: Storage = window.localStorage;
let lo:Location = window.location;
let cookie: string = document.cookie;
​

定義Promise

​
let promise:Promise<number> = new Promise((resolve,reject)=>{
    resolve(111)
});
​
promise.then((value)=>{
    value.toFixed(2)  //value是number型別
});
​

function promise():Promise<number>{
   return new Promise<number>((resolve,reject)=>{
       resolve(1)
   })
}
 
promise().then(res=>{
    console.log(res)
})

當你在使用一些常用的方法的時候，TypeScript 實際上已經幫你做了很多型別判斷的工作了

而他們的定義檔案，則在 TypeScript 核心庫的定義檔案中