javascript - convert blob object to uint8array object (to bytes array)

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// Warning: Blob arrayBuffer() method appeared in the major web browser around 2019-2020 (in Deno v1.0 (2020), in Node.js v15.7.0 (2021)).


const toArray = (blob, callback) => {
    const promise = blob.arrayBuffer();
    promise.then((buffer) => callback(new Uint8Array(buffer)));
};


// Usage example:

const blob = ...;  // Blob object

toArray(blob, (array) => {
    console.log(`array.length=${array.length}`);
    console.log(`array[0]=${array[0]}`);
    console.log(`array[1]=${array[1]}`);
    console.log(`array[2]=${array[2]}`);
    console.log(`...`);
});


// See also:
//   1. https://dirask.com/snippets/JavaScript-convert-Blob-object-to-Uint8Array-object-to-bytes-array-1GMYbp

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// Warning: Blob arrayBuffer() method appeared in the major web browser around 2019-2020 (in Deno v1.0 (2020), in Node.js v15.7.0 (2021)).

const toArray = async (blob) => new Uint8Array(await blob.arrayBuffer());


// Usage example (in async logic):

const blob = ...;                   // Blob object
const array = await toArray(blob);  // Uint8Array object

console.log(`array.length=${array.length}`);
console.log(`array[0]=${array[0]}`);
console.log(`array[1]=${array[1]}`);
console.log(`array[2]=${array[2]}`);
console.log(`...`);


// See also:
//   1. https://dirask.com/snippets/JavaScript-convert-Blob-object-to-Uint8Array-object-to-bytes-array-1GMYbp

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const toArray = (blob, callback) => {
    const reader = new FileReader();
    reader.onload = () => {
        callback(new Uint8Array(reader.result));
    };
    // reader.onerror = () => { /* ... */ };
    reader.readAsArrayBuffer(blob);
};


// Usage example:

const blob = ...;  // Blob object

toArray(blob, (array) => {
    console.log(`array.length=${array.length}`);
    console.log(`array[0]=${array[0]}`);
    console.log(`array[1]=${array[1]}`);
    console.log(`array[2]=${array[2]}`);
    console.log(`...`);
});


// See also:
//   1. https://dirask.com/snippets/JavaScript-convert-Blob-object-to-Uint8Array-object-to-bytes-array-1GMYbp

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const toArray = async (blob) => {
    return new Promise((resolve, reject) => {
        const reader = new FileReader();
        reader.onload = () => {
            resolve(new Uint8Array(reader.result))
        };
        reader.onerror = () => {
            reject();
        };
        reader.readAsArrayBuffer(blob);
    });
};


// Usage example (in async logic):

const blob = ...;                   // Blob object
const array = await toArray(blob);  // Uint8Array object

console.log(`array.length=${array.length}`);
console.log(`array[0]=${array[0]}`);
console.log(`array[1]=${array[1]}`);
console.log(`array[2]=${array[2]}`);
console.log(`...`);


// See also:
//   1. https://dirask.com/snippets/JavaScript-convert-Blob-object-to-Uint8Array-object-to-bytes-array-1GMYbp

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// Note: presented solution works in the older web browsers also.


const toArray = async (blob) => {
    if (blob.arrayBuffer) {
        return new Uint8Array(await blob.arrayBuffer());
    }
    return new Promise((resolve, reject) => {
        const reader = new FileReader();
        reader.onload = () => {
            resolve(new Uint8Array(reader.result))
        };
        reader.onerror = () => {
            reject();
        };
        reader.readAsArrayBuffer(blob);
    });
};


// Usage example (in async logic):

const blob = ...;                   // Blob object
const array = await toArray(blob);  // Uint8Array object

console.log(`array.length=${array.length}`);
console.log(`array[0]=${array[0]}`);
console.log(`array[1]=${array[1]}`);
console.log(`array[2]=${array[2]}`);
console.log(`...`);


// See also:
//   1. https://dirask.com/snippets/JavaScript-convert-Blob-object-to-Int8Array-object-to-bytes-array-jMXbdp