我如何使用angular 4检查资产文件夹中是否存在图像 [英] how can i check if image exists in assets folder using angular 4

问题描述

我需要使用Angular 4检查文件夹中是否存在图像.我有一个从服务器返回的图像名称列表.我需要检查资产文件夹中是否存在该图像.任何帮助或想法都将很好.

I need to check if a image exists in the folder using Angular 4.I have a list of image name that is returned from the server. What I need is to check if that image exists in the asset folder. Any help or idea would be great.

推荐答案

尝试一下.在链接

// The "callback" argument is called with either true or false
// depending on whether the image at "url" exists or not.
function imageExists(url, callback) {
  var img = new Image();
  img.onload = function() { callback(true); };
  img.onerror = function() { callback(false); };
  img.src = url;
}

// Sample usage
var imageUrl = 'http://www.google.com/images/srpr/nav_logo14.png';
imageExists(imageUrl, function(exists) {
  console.log('RESULT: url=' + imageUrl + ', exists=' + exists);
});

我想警告你.小心它，由于它会将图像加载到内存中(如果存在)，因此可能会导致您出现性能问题，无法立即检查更多图像.

I would like to warn you. Becareful with it, It can run you to performance issue for checking more images at once due to it's loading images to memory if exists.

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