diginext-utils/esm/string/guessMimeType.js

README.md

var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, generator) {
    function adopt(value) { return value instanceof P ? value : new P(function (resolve) { resolve(value); }); }
    return new (P || (P = Promise))(function (resolve, reject) {
        function fulfilled(value) { try { step(generator.next(value)); } catch (e) { reject(e); } }
        function rejected(value) { try { step(generator["throw"](value)); } catch (e) { reject(e); } }
        function step(result) { result.done ? resolve(result.value) : adopt(result.value).then(fulfilled, rejected); }
        step((generator = generator.apply(thisArg, _arguments || [])).next());
    });
};
import { createReadStream } from "fs";
export function guessMimeType(filepath) {
    return __awaiter(this, void 0, void 0, function* () {
        return new Promise((resolve, reject) => {
            const stream = createReadStream(filepath, {
                start: 0,
                end: 11, // Read only first 12 bytes
            });
            let buffer = new Uint8Array(0);
            stream.on("data", (chunk) => {
                const chunkArray = new Uint8Array(Buffer.isBuffer(chunk) ? chunk : Buffer.from(chunk));
                // Manual concatenation
                const newBuffer = new Uint8Array(buffer.length + chunkArray.length);
                newBuffer.set(buffer);
                newBuffer.set(chunkArray, buffer.length);
                buffer = newBuffer;
            });
            stream.on("end", () => {
                // Convert to hex string
                const toHex = (arr, start, end) => {
                    return Array.from(arr.slice(start, end))
                        .map((b) => b.toString(16).padStart(2, "0"))
                        .join("");
                };
                const signature = toHex(buffer, 0, 4);
                switch (signature) {
                    case "89504e47":
                        resolve("image/png");
                        break;
                    case "47494638":
                        resolve("image/gif");
                        break;
                    case "52494646":
                        if (buffer.length >= 12) {
                            const webpSignature = toHex(buffer, 8, 12);
                            if (webpSignature === "57454250") {
                                resolve("image/webp");
                            }
                            else {
                                resolve("unknown");
                            }
                        }
                        else {
                            resolve("unknown");
                        }
                        break;
                    case "00000018":
                    case "0000001c":
                    case "00000020":
                        resolve("video/mp4");
                        break;
                    case "66747970":
                        resolve("video/quicktime");
                        break;
                    case "1a45dfa3":
                        resolve("video/webm");
                        break;
                    case "000001ba":
                    case "000001b3":
                        resolve("video/mpeg");
                        break;
                    default:
                        if (signature.startsWith("ffd8ff")) {
                            resolve("image/jpeg");
                        }
                        else {
                            resolve("application/octet-stream");
                        }
                }
            });
            stream.on("error", reject);
        });
    });
}
export default guessMimeType;
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