Question

I have a temporary File API store (HTML5) but I can t check whether a file exists or not. Is there a simple way to check it? Do I have to actually try and read the file to find out?

A search around has yielded me nothing concrete

进行同步检查是可能的吗?

Answer 1

你必须读到档案。以下例子基于:。页: 1 (一) 收集所有错误,你可能希望过滤。

    var errorHandler = function() {
        // File is not readable or does not exist!
    };
    fs.root.getFile( log.txt , {}, function(fileEntry) {
        fileEntry.file(function(file) {
            var reader = new FileReader();
            reader.onloadend = function() {
                // The file exists and is readable
            };
            reader.readAsText(file);
        }, errorHandler);
    }, errorHandler);

The synchronous method is only available to Web Workers, due to their blocking nature. The error handling is slightly different.

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