Looking for a demonstration on how to utilize fabricjs.d.ts in TypeScript?

Question

Looking for a demonstration on how to utilize fabricjs.d.ts in TypeScript?

I am currently using fabricjs in a project that I am transitioning to TypeScript, but I am having trouble understanding how to integrate it. In the past, I would create custom objects like this:

my.namespace.Control = fabric.util.createClass(fabric.Object, {
    id: "",
    type: 'Control',
    color: "#000000", 
    ...
});

For my new project, I have downloaded the TypeDefinition file from this source, but I am unsure of how to proceed.

Upon inspecting the .d.ts file, it seems that fabric.Object is not recognized as a Function, meaning it cannot be passed to createClass. Additionally, createClass itself returns void, preventing me from assigning its value to a variable.

Assuming all these issues were resolved, how should I structure this to adhere to TypeScript conventions? More specifically, how do I export it for use elsewhere when the Control class is required?

Has anyone successfully implemented this and can provide examples?

javascript angularjs typescript fabricjs

Answer 1

Answer №1

To create a TypeScript class that extends a Fabric class, you can define the following interfaces and class:

export interface IMindObjectOptions {
    item: IMindItem;
}

export interface IMindExpanderOptions extends IMindObjectOptions {
    x: number;
    y: number;
    radius: number;
    isExpanded: boolean;
}

export class MindExpander extends fabric.Circle implements IMindObjectOptions {

    public constructor(options: IMindExpanderOptions) {
        const circleOptions: ICircleOptions = {
            originX: "center",
            originY: "center",
            left: options.x,
            top: options.y,
            radius: options.radius,
            stroke: "#000000",
            fill: options.isExpanded ? "#00FFFF": "#00FF00",
            selectable: false
        };
        super(circleOptions);
        this.item = options.item;
    }

    public readonly item: IMindItem;
}

Although the code above functions properly in a browser environment, it may encounter issues when executed in Node.js.

If you intend to use the code in a Node.js setting, like for running unit tests without a browser, follow these steps:

import {assert} from "chai";
import * as f from 'fabric';
import {ITextOptions} from "fabric";

declare function require(s: string): any;
declare const __dirname: string;

const fabric = require("fabric").fabric;

interface ITextConstructor {
    new(text: string, options: ITextOptions): f.Text;
}
function getTextConstructor(): ITextConstructor {
    return fabric.Text;
}

describe("Node.js configuration", function () {
    it("Fabric module is correctly imported", function () {
        const x = fabric.Text as f.Text;
        assert.equal(typeof x, "function");
    });
    it("The Fabric class can be extended", function () {
        class SubText extends getTextConstructor() {
            public constructor(text: string, options: fabric.ITextOptions) {
                super(text, options);
            }
        }

        const c = new SubText("Hello", {left: 100, top: 100});
        assert.equal(c.text, "Hello");
        assert.isNotNull(c);
    });
});

Answer 2

To create a TypeScript class that extends a Fabric class, you can define the following interfaces and class:

export interface IMindObjectOptions {
    item: IMindItem;
}

export interface IMindExpanderOptions extends IMindObjectOptions {
    x: number;
    y: number;
    radius: number;
    isExpanded: boolean;
}

export class MindExpander extends fabric.Circle implements IMindObjectOptions {

    public constructor(options: IMindExpanderOptions) {
        const circleOptions: ICircleOptions = {
            originX: "center",
            originY: "center",
            left: options.x,
            top: options.y,
            radius: options.radius,
            stroke: "#000000",
            fill: options.isExpanded ? "#00FFFF": "#00FF00",
            selectable: false
        };
        super(circleOptions);
        this.item = options.item;
    }

    public readonly item: IMindItem;
}

Although the code above functions properly in a browser environment, it may encounter issues when executed in Node.js.

If you intend to use the code in a Node.js setting, like for running unit tests without a browser, follow these steps:

import {assert} from "chai";
import * as f from 'fabric';
import {ITextOptions} from "fabric";

declare function require(s: string): any;
declare const __dirname: string;

const fabric = require("fabric").fabric;

interface ITextConstructor {
    new(text: string, options: ITextOptions): f.Text;
}
function getTextConstructor(): ITextConstructor {
    return fabric.Text;
}

describe("Node.js configuration", function () {
    it("Fabric module is correctly imported", function () {
        const x = fabric.Text as f.Text;
        assert.equal(typeof x, "function");
    });
    it("The Fabric class can be extended", function () {
        class SubText extends getTextConstructor() {
            public constructor(text: string, options: fabric.ITextOptions) {
                super(text, options);
            }
        }

        const c = new SubText("Hello", {left: 100, top: 100});
        assert.equal(c.text, "Hello");
        assert.isNotNull(c);
    });
});

Answer 3

Answer №2

When incorporating fabricjs.d.ts into your code, the traditional approach was to place it at the beginning of your file :

/// <reference path="path/to/your/fabricjs.d.ts" />

If you acquire it through tsd, you must reference your tsd.d.ts bundle file.

However, with typescript 1.6.2 and vscode, all you need to do is download the reference file via tsd to access the definitions in your code.

Inside the d.ts file, there are two method signatures:

createClass(parent: Function, properties?: any): void;

createClass(properties?: any): void;

Hence, your code may seem invalid because fabric.Object as the interface IObjectStatict cannot be assigned to type Function. To resolve this, you can cast fabric.Object as a Function by:

my.namespace.Control = fabric.util.createClass(<Function>fabric.Object, {
  id: '',
  type: 'Control',
  color: '#000000', 
  ...
});

Answer 4

When incorporating fabricjs.d.ts into your code, the traditional approach was to place it at the beginning of your file :

/// <reference path="path/to/your/fabricjs.d.ts" />

If you acquire it through tsd, you must reference your tsd.d.ts bundle file.

However, with typescript 1.6.2 and vscode, all you need to do is download the reference file via tsd to access the definitions in your code.

Inside the d.ts file, there are two method signatures:

createClass(parent: Function, properties?: any): void;

createClass(properties?: any): void;

Hence, your code may seem invalid because fabric.Object as the interface IObjectStatict cannot be assigned to type Function. To resolve this, you can cast fabric.Object as a Function by:

my.namespace.Control = fabric.util.createClass(<Function>fabric.Object, {
  id: '',
  type: 'Control',
  color: '#000000', 
  ...
});

Looking for a demonstration on how to utilize fabricjs.d.ts in TypeScript?

Answer №1

Answer №2

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