反应，如何在初始化之前调用然后块中的函数或任何正确的方法？

Question

我已经为我的 React 组件构建了一个带有 face-api.js 的 javascript 函数，它将 return/console 我的面部检测器框的宽度和高度。我在几个地方尝试了 console.log 它似乎工作正常直到模型（面部识别模型）。

但是当我为人脸检测器编写异步函数来检测人脸和控制台时。它给我错误-

Unhandled rejection(Reference Error): Cannot access 'handledImage' before initialization

这也是屏幕截图。

我想不通，如何解决？

有我的代码faceDetector.js

import * as faceapi from "face-api.js";

//passing image from my react compoenent
const faceDetector = (image) => {
    const imageRef = image;

    const loadModels = async () => {
       // models are present in public and they are getting loaded
        const MODEL_URL = process.env.PUBLIC_URL + "/models";
        Promise.all([
            faceapi.nets.tinyFaceDetector.loadFromUri(MODEL_URL),
            faceapi.nets.faceLandmark68Net.loadFromUri(MODEL_URL),
            faceapi.nets.faceRecognitionNet.loadFromUri(MODEL_URL),
            faceapi.nets.faceExpressionNet.loadFromUri(MODEL_URL)
        ])
             // this is rising the issue. I want to call this function after my models loaded so it can detect face
            .then(handleImage)
            .catch((e) => console.error(e));
    };
    loadModels();

    // this function should detect the face from imageRef and should console the size of detector
    const handleImage = async () => {
        const detections = await faceapi
            .detectSingleFace(imageRef, new faceapi.TinyFaceDetectorOptions())
        console.log(`Width ${detections.box._width} and Height ${detections.box._height}`);
    }


}



export {faceDetector}

Answer 1

您需要更改函数声明的顺序。您不能在声明变量之前调用 const 变量。

//passing image from my react component
const faceDetector = (image) => {
  const imageRef = image;


  // this function should detect the face from imageRef and should console the size of detector
  const handleImage = async () => {
    const detections = await faceapi
        .detectSingleFace(imageRef, new faceapi.TinyFaceDetectorOptions())
    console.log(`Width ${detections.box._width} and Height ${detections.box._height}`);
}

   const loadModels = async () => {
   // models are present in public and they are getting loaded
    const MODEL_URL = process.env.PUBLIC_URL + "/models";
    Promise.all([
        faceapi.nets.tinyFaceDetector.loadFromUri(MODEL_URL),
        faceapi.nets.faceLandmark68Net.loadFromUri(MODEL_URL),
        faceapi.nets.faceRecognitionNet.loadFromUri(MODEL_URL),
        faceapi.nets.faceExpressionNet.loadFromUri(MODEL_URL)
    ])
         // this is rising the issue. I want to call this function after my models loaded so it can detect face
        .then(handleImage)
        .catch((e) => console.error(e));
   };
   loadModels();


}

反应，如何在初始化之前调用然后块中的函数或任何正确的方法？

react, how to call a function inside then block before initializing it or any proper way?

javascript

face-recognition

reactjs

face-api

react-hooks