Check uploaded file size

Question

I have file uploader component and need to add size validator in it

This is the code for the validator

export const filesDimensionValidator =
  (maxWidth: number, maxHeight: number): ValidatorFn =>
  (control: AbstractControl): ValidationErrors | null => {
    const value: IUploadFileControl = control.value;

    if (value == null) {
      return null;
    }

    for (const x of value.allFiles) {
      if (x.size > maxFileSize) {
        return { file_max_size: VALIDATION_LABEL_ATTACHMENT_MAX_SIZE };
      }
    }

    return null;
  };

If the for loop x parameter has type File.

Only images here.

How to get the width and height of the image in this file?

Answer 1

Create an image using Image and then get the desired dimensions.

You can use file.type to verify that x is an image:

Try this:

// add mime type check
if (x?.type.includes('image/')) {
  
  const url = URL.createObjectURL(x);
  const img = new Image();

  img.onload = function () {
    console.log(img.width, img.height);
    URL.revokeObjectURL(img.src);
  };

  img.src = url;

}

edit

Get the size simultaneously:

// pass file to the method and hold execution
console.log(await this.getDimensions(x));

// method that gets and return dimensions from a file
  getDimensions(x: File) : Promise<{width:number, height:number}> {
    return new Promise((resolve, reject) => {
      const url = URL.createObjectURL(x);
      const img = new Image();
      img.onload = () => {
        URL.revokeObjectURL(img.src);
        resolve({ width: img.width, height: img.height });
      };
      img.src = url;
    });
  }