Introduction to Line-Parser

The line-parser package is a powerful and flexible library designed to simplify the process of parsing and manipulating text lines. With numerous built-in APIs, it allows developers to effectively handle various text parsing scenarios with ease and precision. In this blog post, we will delve into the features of line-parser, showcasing its capabilities through a series of practical code snippets and an app example.

Getting Started with Line-Parser

To start using line-parser, you need to install it via npm:

  npm install line-parser

Useful API Examples

Reading Text from a File

  const fs = require('fs');
  const { parseLines } = require('line-parser');

  fs.readFile('sample.txt', 'utf8', (err, data) => {
    if (err) throw err;
    const lines = parseLines(data);
    console.log(lines);
  });

This code snippet demonstrates how to read lines of text from a file and parse them into an array of strings using the parseLines function.

Filtering Lines

  const { filterLines } = require('line-parser');

  const data = `line one
                line two
                line three`;
  const filteredLines = filterLines(data, line => line.includes('two'));
  console.log(filteredLines);

In this example, the filterLines function is used to filter lines that contain the word ‘two’.

Transforming Lines

  const { transformLines } = require('line-parser');

  const data = `line one
                line two
                line three`;
  const uppercasedLines = transformLines(data, line => line.toUpperCase());
  console.log(uppercasedLines);

This snippet showcases how to transform lines of text to uppercase using the transformLines function.

Splitting and Joining Lines

  const { splitLines, joinLines } = require('line-parser');

  const data = `line one|line two|line three`;
  const lines = splitLines(data, '|');
  const joinedLines = joinLines(lines, '\n');
  console.log(joinedLines);

The splitLines and joinLines functions allow for splitting lines based on a delimiter and joining them back with a new delimiter respectively.

App Example Using Line-Parser APIs

Below is an example of a simple application that reads a text file, filters out lines containing a specified keyword, transforms the lines to uppercase, and writes the result to a new file.

  const fs = require('fs');
  const { parseLines, filterLines, transformLines, joinLines } = require('line-parser');

  fs.readFile('input.txt', 'utf8', (err, data) => {
    if (err) throw err;

    const lines = parseLines(data);
    const filteredLines = filterLines(lines, line => line.includes('keyword'));
    const transformedLines = transformLines(filteredLines, line => line.toUpperCase());
    const result = joinLines(transformedLines, '\n');

    fs.writeFile('output.txt', result, (err) => {
      if (err) throw err;
      console.log('File written successfully!');
    });
  });

This example integrates several line-parser APIs to process text in a practical application.

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