Node.js Requires Chilkat v11.7.0+

Get Every Occurrence of a Label in a PDF

See more PDF Text Extraction Examples

Demonstrates the "labelOccurrence" option. When the same label appears more than once (for example "Total:" on each of several receipts), "first" (the default) uses the first occurrence, "all" returns every occurrence with its page, and a number selects one occurrence. Node.js

NODEJS_PRELUDE

function chilkatExample() {

    var success = false;

    //  This example requires the Chilkat API to have been previously unlocked.
    //  See Global Unlock Sample for sample code.

    //  The PDF used in this example (three receipts, one per page) is available at three_receipts.pdf

    var pdf = new chilkat.Pdf();
    success = pdf.LoadFile("qa_data/pdf/three_receipts.pdf");
    if (success == false) {
        console.log(pdf.LastErrorText);
        return;
    }

    var json = new chilkat.JsonObject();
    var jsonOut = new chilkat.JsonObject();

    //  Each of the three pages is a receipt with a "Total:" line.
    json.UpdateString("label","Total");
    json.UpdateString("labelValue","right");

    //  By default only the first occurrence (in reading order) is used.
    success = pdf.ExtractText("text",json,jsonOut);
    if (success == false) {
        console.log(pdf.LastErrorText);
        return;
    }

    console.log("First total: " + jsonOut.StringOf("text"));

    //  labelOccurrence "all" returns every occurrence.  The "text" member holds the values joined
    //  by line breaks, and labelMatches has one entry per occurrence with its page.
    json.UpdateString("labelOccurrence","all");
    success = pdf.ExtractText("text",json,jsonOut);
    if (success == false) {
        console.log(pdf.LastErrorText);
        return;
    }

    var i = 0;
    var count_i = jsonOut.SizeOfArray("labelMatches");
    while (i < count_i) {
        jsonOut.I = i;
        console.log("Page " + jsonOut.IntOf("labelMatches[i].page") + " total: " + jsonOut.StringOf("labelMatches[i].text"));
        i = i+1;
    }

    //  A number selects one occurrence: 2 is the second.
    json.UpdateInt("labelOccurrence",2);
    success = pdf.ExtractText("text",json,jsonOut);
    if (success == false) {
        console.log(pdf.LastErrorText);
        return;
    }

    console.log("Second total: " + jsonOut.StringOf("text"));

    //  The occurrences are counted over the selected pages, so combining "pages" with the label
    //  is another way to pick one receipt:
    json.UpdateString("labelOccurrence","first");
    json.UpdateString("pages","3");
    json.UpdateString("label","Receipt No.");
    success = pdf.ExtractText("text",json,jsonOut);
    if (success == false) {
        console.log(pdf.LastErrorText);
        return;
    }

    console.log("Receipt number on page 3: " + jsonOut.StringOf("text"));

    //  Sample output:

    //  First total: $19.86
    //  Page 1 total: $19.86
    //  Page 2 total: $17.34
    //  Page 3 total: $23.62
    //  Second total: $17.34
    //  Receipt number on page 3: 1003

}

chilkatExample();