59 lines
1.1 KiB
TypeScript
59 lines
1.1 KiB
TypeScript
import type { Attachment } from "@root/model/attachment"
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type ReadFileFormat = "text" | "url" | "array" | "binary";
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type ReadFileOption<T extends ReadFileFormat> = T extends "text" | "url"
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? Promise<string>
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: T extends "array"
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? Promise<ArrayBuffer>
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: T extends "binary"
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? Promise<Attachment>
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: Promise<null>;
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export const readFile = <T extends ReadFileFormat>(
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file: File,
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format?: T
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): ReadFileOption<T> => <ReadFileOption<T>>new Promise((resolve, reject) => {
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const reader = new FileReader()
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switch (format) {
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case "text":
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reader.readAsText(file)
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break
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case "url":
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reader.readAsDataURL(file)
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break
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case "array":
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reader.readAsArrayBuffer(file)
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break
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case "binary":
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reader.readAsBinaryString(file)
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break
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default:
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reader.readAsText(file)
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break
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}
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reader.onload = (): void => {
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if (!reader.result) {
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return reject(new Error("File is empty"))
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}
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if (format === "binary") {
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return resolve({
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name: file.name,
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content: reader.result as "string",
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mimetype: file.type,
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})
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}
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return resolve(reader.result)
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}
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reader.onerror = (): void => reject(new Error("Data conversion error"))
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})
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