Object key values are empty but had data-CodePudding

So I have an object that at certain point gets a value for each key but suddenly loses all the key values.

the key values just get empty and at the console there's a message at the object saying: "this value was evaluated upon first expanding. it may have changed since then", but i dont change is value anywhere else.

My service:

image = {
  name: "",
  path: "",
  data: ""
};

async loadFileData(fileNames: string[]) {
    for (let f of fileNames) {
      const filePath = `${IMAGE_DIR}/${f}`;
      const readFile = await Filesystem.readFile({
        directory: Directory.Data,
        path: filePath
      });

      this.images.push({
        name: f,
        path: filePath,
        data: `data:image/jpeg;base64,${readFile.data}`
      });

      // testing
      this.image.name = f;
      this.image.path = filePath;
      this.image.data = `data:image/jpeg;base64,${readFile.data}`;
    }

    console.log('my image: ', this.image);
  }

  async loadFiles() {
    this.images = [];

    const loading = await this.loadingController.create({
      message: 'loading data...',
    });
    await loading.present();

    Filesystem.readdir({
      directory: Directory.Data,
      path: IMAGE_DIR
    }).then(result => {
      this.loadFileData(result.files);
    }, async err => {
      console.log('err: ', err);
      await Filesystem.mkdir({
        directory: Directory.Data,
        path: IMAGE_DIR
      });
    }).then(_ => {
      loading.dismiss();
    });
  }

My component:

this.photoService.loadFiles();

console.log('my object: ', this.photoService.image);

console.log('is my object empty? ', JSON.stringify(this.photoService.image) === '{}');

Then what happens when I press the button to expand?
Now it shows that data is changed to "whatever" etc., but its original value image = { name: "", path: "", data: ""}; is still shown (logged).

The expanded form shows the new data. The empty values belonged to old data.

CodePudding user response：

It about asyn and memory of javascript .

When you run console.log(this.photoService.image)

this.photoService.loadFiles(); is running

Value of this : { name: "", path: "", data: ""}

When you check value of console :

this.photoService.loadFiles(); finished

memory of this.photoService.image was updated

Value of this => { name: "xxx....", path: "yyy...", data: "zzz..."}