In this tutorial, we will be discussing how to extract a table from a PDF file using the pdfjs-dist library in an Angular application. This is a great skill to have, as it allows you to easily access and manipulate data contained in PDF files. By the end of this tutorial, you will be able to extract a table from a PDF file and store it in an array for further use in your Angular application.
Before we begin, it is important to note that this tutorial assumes that you have a basic understanding of Angular and JavaScript. If you are new to Angular, I recommend checking out the official Angular documentation to get started.
To get started, you will need to install the pdfjs-dist library in your Angular project. You can do this by running the following command in your terminal:
npm install pdfjs-dist
Once the library is installed, you can start using it in your Angular application. First, you will need to import the pdfjsLib object from the pdfjs-dist library. You can do this by adding the following line to the top of your component file:
import * as pdfjsLib from 'pdfjs-dist';
Next, you will need to create a function that will be responsible for extracting the table from the PDF file. This function should take the file path of the PDF file as a parameter. Here is an example of what this function might look like:
async extractTable(filePath: string) {
const loadingTask = pdfjsLib.getDocument(filePath);
const pdf = await loadingTask.promise;
const page = await pdf.getPage(1);
const content = await page.getTextContent();
const items = content.items;
const table = [];
let row = [];
for (let i = 0; i < items.length; i++) {
const item = items[i];
if (item.str === '
') {
row.push('');
} else {
row.push(item.str);
}
if (item.transform[4] === 0) {
table.push(row);
row = [];
}
}
return table;
}
Let's break down what this function is doing. First, it uses the getDocument() method from the pdfjsLib object to load the PDF file. This method returns a loadingTask object, which we can use to wait for the file to finish loading. Once the file is loaded, we can use the getPage() method to retrieve the first page of the PDF file. We then use the getTextContent() method to retrieve the text content of the page as an array of TextItem objects. Each TextItem object represents a piece of text, such as a single character or a word. We can use these objects to extract the table from the PDF file. To do this, we first create an empty table array and an empty row array. We then loop through the TextItem objects and add each piece of text to the current row. If the text is a newline character, we add an empty string to the row instead. Once we reach the end of a row, we add the row to the table array and create a new row. We continue this process until we have extracted all of the rows from the PDF file. Finally, we return the table array.
Now that we have a function for extracting the table from the PDF file, we can use it in our Angular application. For example, we might create a button that, when clicked, extracts the table from the PDF file and displays it in the console. Here is an example of what this might look like:
<button (click)="extract()">Extract</button>
In the component file, we can define the extract() method as follows:
async extract() {
const table = await this.extractTable('path/to/pdf/file.pdf');
console.log(table);
}
When the button is clicked, the extract() method is called. This method uses the extractTable() function that we defined earlier to extract the table from the PDF file. The table is then logged to the console. You can modify this code to display the table in the user interface or to perform other actions with the data.
In this tutorial, we have discussed how to extract a table from a PDF file using the pdfjs-dist library in an Angular application. This is a great skill to have, as it allows you to easily access and manipulate data contained in PDF files. By following the steps outlined in this tutorial, you will be able to extract a table from a PDF file and store it in an array for further use in your Angular application.
References
| Title | Author | Year | Link |
|---|---|---|---|
| PDF.js | Mozilla | 2017 | https://mozilla.github.io/pdf.js/ |
| Angular | 2021 | https://angular.io/ |