我有一个无法正常工作的 javascript 函数

Question

function filter_effect(effect_name){
    var tmp_img = document.createElement("IMG");
    tmp_img.src = get_cropped_image()
    tmp_img.style.display = "none"
    Caman(tmp_img, function (){
      this[effect_name](); 
          this.render(function () {
              change_picture(this.canvas.toDataURL("image/jpeg"))
      });
    });
}

this is my code and when I run this I get this error

Uncaught TypeError: this[effect_name] is not a function

Can anyone help that what I should do to fix this?

Answer 1

You should change your function call and pass the this . Change this line, it would be solved:

Caman.call(this, tmp_img, function (){
   /* Your callback function body */
});

Here this means the filter_effect function. When you want to change the this object in function calls, you have to use .apply() or .call() to change it.

Here is a reference for this post.

Answer 2

您必须澄清“this”引用值，它必须是指一个 javascript 对象，其 effect_name 属性被声明为函数，使用浏览器的调试器对其值进行审查