问Typescript:未捕获ReferenceError:未定义变形

EN

Uncaught ReferenceError: Morph is not defined
    at sketch (sketch.ts:7)
    at new p5 (sketch.ts:28)
    at Object.<anonymous> (sketch.ts:28)
    at c (sketch.ts:28)
    at Function.r.import (sketch.ts:28)
    at sketch.ts:28

import 'p5'
import './morph'


var sketch = (p: p5) => {

    const morph = new Morph();

    p.preload = () => {

    }

    p.setup = () => {
        p.createCanvas(p.windowWidth, p.windowHeight);
        morph.setup(p);
    }

    p.windowResized = () => {
        p.resizeCanvas(p.windowWidth, p.windowHeight);
    }

    p.draw = () => {
        p.background(100);
        morph.draw(p);        
    }
}

var sketchP = new p5(sketch);