@nosferatu500/textract/lib/extractors/images.js

Extracting text from files of various type including html, pdf, doc, docx, xls, xlsx, csv, pptx, png, jpg, gif, rtf, text/*, and various open office.

const { exec } = require("child_process");
const util = require("../util");

function tesseractExtractionCommand(options, inputFile, outputFile) {
    let cmd = `tesseract ${inputFile} ${outputFile}`;
    if (options.tesseract) {
        if (options.tesseract.lang) {
            cmd += ` -l ${options.tesseract.lang}`;
        } else if (options.tesseract.cmd) {
            cmd += ` ${options.tesseract.cmd}`;
        }
    }
    cmd += " quiet";
    return cmd;
}

function extractText(filePath, options, cb) {
    const execOptions = util.createExecOptions("images", options);
    util.runExecIntoFile("tesseract", filePath, options, execOptions, tesseractExtractionCommand, cb);
}

function testForBinary(options, cb) {
    exec("tesseract", function (error, stdout, stderr) {
        let msg;
        // checking for content of help text
        if (
            (error && error.toString().includes("Usage:")) ||
            (stderr && stderr.toString().includes("Usage:")) ||
            (stdout && stdout.toString().includes("Usage:"))
        ) {
            cb(true);
        } else {
            msg =
                "INFO: 'tesseract' does not appear to be installed, " + "so textract will be unable to extract images.";
            cb(false, msg);
        }
    });
}

module.exports = {
    types: ["image/png", "image/jpeg", "image/gif"],
    extract: extractText,
    test: testForBinary,
};