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Rémy F.
Rémy F.

Posted on

Async Promise-based FileReader one-liner

#javascript #filereader

The Line 

const cat = (f) =>
  new Promise(resolve => Object.assign(new FileReader(), {onload(){resolve(this.result)}}).readAsText(f));
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Usage 

<input type="file" onchange="cat(files[0]).then(console.log)">
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