[英]How to get string base64 in a variable?
This is my code: but not get the string base64 in my variable. 这是我的代码:但没有在我的变量中获取字符串base64。 I need the string base64 in this variable var base64. 我在此变量var base64中需要字符串base64。 I have seen other issues but none of them meets what I need 我看过其他问题,但没有一个满足我的需求
<input type:file multiple id="files">
<script>
function listarchivos(){
var base64; //in this variable i need the base64
var selectedFile = document.getElementById("files").files;
var fileToLoad = selectedFile[0];
getBase64(fileToLoad).then(
data => alert(data)
);
}
//This is my function for get base64, but not return the string base64
function getBase64(file) {
return new Promise((resolve, reject) => {
const reader = new FileReader();
reader.readAsDataURL(file);
reader.onload = () => resolve(reader.result);
reader.onerror = error => reject(error);
return Promise.resolve(reader.result)
});
}
</script>
the function that I have already complies with obtaining the base64 string of the file that is given as a parameter, what I can not do is get access to that string to assign it to a variable and use it. 我已经符合获取作为参数给出的文件的base64字符串的函数,我不能做的就是访问该字符串以将其分配给变量并使用它。
I just need you to tell me how I can get access to that base64 chain, I just need it in a variable that can be handled as desired. 我只需要您告诉我如何访问该base64链,我只需要一个可以根据需要处理的变量即可。
I have already tried the following options
var base64 = getBase64(fileToLoad).then(
data => alert(data)
); //this not works
getBase64(fileToLoad).then(
data => base64 = data
); //This not works
getBase64(fileToLoad).then(
data => return{data}
);//this not works
Since Promise
makes the function asynchronous, the following code would start running getBase64()
and continuously executing console.log(base64)
which is not defined yet. 由于Promise
使该函数异步进行,因此以下代码将开始运行getBase64()
并继续执行未定义的console.log(base64)
。
function listarchivos() {
base64; //in this variable i need the base64
var selectedFile = document.getElementById("files").files;
var fileToLoad = selectedFile[0];
getBase64(fileToLoad).then(
data => {
base64 = data;
}
);
console.log(base64) // undefined
}
So you should await
for getBase64()
be done or use a callback like the followings. 因此,您应该await
getBase64()
完成或使用如下所示的回调。
await example 1 等待示例1
async function listarchivos() { var base64; //in this variable i need the base64 var selectedFile = document.getElementById("files").files; var fileToLoad = selectedFile[0]; await getBase64(fileToLoad).then( data => { alert(data); base64 = data; } ); console.log(base64) } //This is my function for get base64, but not return the string base64 function getBase64(file) { return new Promise((resolve, reject) => { const reader = new FileReader(); reader.readAsDataURL(file); reader.onload = () => resolve(reader.result); reader.onerror = error => reject(error); return Promise.resolve(reader.result) }); } $('#files').on('change', listarchivos)
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script> <input type="file" multiple id="files">
await example 2 等待示例2
async function listarchivos() { var base64; //in this variable i need the base64 var selectedFile = document.getElementById("files").files; var fileToLoad = selectedFile[0]; base64 = await getBase64(fileToLoad).then( data => { return data; } ); console.log(base64) } //This is my function for get base64, but not return the string base64 function getBase64(file) { return new Promise((resolve, reject) => { const reader = new FileReader(); reader.readAsDataURL(file); reader.onload = () => resolve(reader.result); reader.onerror = error => reject(error); return Promise.resolve(reader.result) }); } $('#files').on('change', listarchivos) function DoSomething() { console.log(base64) }
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script> <input type="file" multiple id="files">
callback 打回来
var base64; function listarchivos() { var selectedFile = document.getElementById("files").files; var fileToLoad = selectedFile[0]; getBase64(fileToLoad).then( data => { base64 = data; DoSomething() } ); } //This is my function for get base64, but not return the string base64 function getBase64(file) { return new Promise((resolve, reject) => { const reader = new FileReader(); reader.readAsDataURL(file); reader.onload = () => resolve(reader.result); reader.onerror = error => reject(error); return Promise.resolve(reader.result) }); } $('#files').on('change', listarchivos) function DoSomething() { console.log(base64) }
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script> <input type="file" multiple id="files">
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