How to import JQuery into a Typescript file?

问题:

Update

No import was required. Instead, I needed to add a reference to the top of the file. So the first line of my WebAPI.js should have been /// <reference path ="../typings/jquery/jquery.d.ts"/> instead of import { $ } from '../jquery-3.1.1';

---

I am trying to import jQuery to use in a Typescript file, but I am receiving a variety of errors with everything I try. I followed the solutions here and here, but without any luck.

tsconfig.json

{
    "compilerOptions": {
        "removeComments": true,
        "preserveConstEnums": true,
    "out": "Scripts/CCSEQ.Library.js",
    "module": "amd",
        "sourceMap": true,
    "target": "es5",
    "allowJs": true
}

WebAPI.js

import { $ } from '../jquery-3.1.1';

export class ExpenseTransaction extends APIBase {

    constructor() {
        super();
    }

    Get(): void {
        let expenses: Array<Model.ExpenseTransaction>;
        let self = this;
        $.ajax({
            url: this.Connection,
            type: "GET",
            contentType: "application/json",
            dataType: "json",
            success: function (data: any): void {
                expenses = self.ConvertToEntity(data.value);
            },
            error: function (data: any): void { console.log(data.status); }
        });
    };
}

I have also tried import * as $ from '../jquery.3.1.1'

Errors

• Module jquery-3.1.1 has no exported member $
• Property ajax does not exist on type (selector: any, context: any) => any

回答1:

You have to import it as import * as $ from "jquery";, according to typescript's documentation, and jquery's definition file the module is defined as an ambient module:

declare module "jquery" {
    export = $;
}

According to this:

Ambient declarations is a promise that you are making with the compiler. If these do not exist at runtime and you try to use them, things will break without warning.

Hope it helps!

回答2:

An import is not required. Instead, add a reference to the Typescript definition file the top of the file. So the first line of the WebAPI.js should be

/// <reference path ="../typings/jquery/jquery.d.ts"/> 

instead of

import { $ } from '../jquery-3.1.1';

According to the DefinitelyTyped wiki:

A TypeScript declaration file is way of defining the types, functions and parameters in an external third-party JavaScript library. By using a declaration file in your TypeScript code will enable Intellisense and type checking against the external library you are using.

jquery.d.ts is a part of the DefinitelyTyped Library found on GitHub. Definitely Typed can be include in Visual Studio projects via the NuGet Package Manager.

回答3:

do this : after installing jquery with npm or used with cdn

first:

npm install @types/jquery --save-dev

and after:

import * as $ from 'jquery';

回答4:

Try replacing your import with declare let $ : any;