Easy-Read-Last-Lines

High performance read the last N lines in the file or text across platforms. (like tail -n)

Table of contents

• Feature
• Installation
• Usage
• Functions
• License
• End

Feature

• High performance read
• Compatible with newlines on different platforms/format: \r, \n, \r\n
• Support setting character encoding
• Support get a String or Buffer object from file

Installation

npm install easy-read-last-lines

Usage

const erll = require('easy-read-last-lines');

Read last N lines string from File

let fielPath='YOUR_FILE_PATH';

// Read last N lines string from File - Asynchronously
erll.readFromFile(filePath, 3).then(function(lines) {
    console.log(lines);
}).catch(function(err) {
    console.log(err.message);
});

//  Read last N lines string from File - Synchronously
let lines = await erll.readFromFile(filePath, 3, 'utf8');
console.log(lines);

// Read an array of last N line string from File
let linesArray = await erll.readArrayFromFile(filePath, 3, 'utf8');
console.log(linesArray);

Read last N lines buffer data from File

let fielPath='YOUR_FILE_PATH';

// Asynchronously
erll.readBufferFromFile(filePath, 1).then(function(buffer) {
    console.log(buffer.toString('base64'));
}).catch(function(err) {
    console.log(err.message);
});

// Synchronously
let buffer = await erll.readBufferFromFile(filePath, 1);
console.log(buffer.toString('base64'));

Read last N lines string from Text

var text = `
Easy 
Read 
Last
Line`;
var text2 = `Easy\nRead\rLast\r\nLine`
    
// Read last N lines string from Text
var lines = erll.readFromText(text, 2);
console.log(lines);

// Read an array of last N line string from Text
var linesArray = erll.readArrayFromText(text2, 3);
console.log(linesArray);

Convert multiline text to array of string

var text = `Easy\nRead\rLast\r\nLine`;

console.log(erll.linesToArray(lines));

Functions

• readFromFile(filePath, maxLine, [encoding]): Promise

  • filePath: file path(direct or relative path to file)
  • maxLine: max number of last lines to read in
  • encoding: When converting between Buffers and strings, a character encoding may be specified. If no character encoding is specified, UTF-8 will be used as the default. buffers-and-character-encodings

• readArrayFromFile(filePath, maxLine, [encoding]): Promise

  • filePath: file path(direct or relative path to file)
  • maxLine: max number of last lines to read in
  • encoding: When converting between Buffers and strings, a character encoding may be specified. If no character encoding is specified, UTF-8 will be used as the default. buffers-and-character-encodings

• readBufferFromFile(filePath, maxLine): Promise

  • filePath: file path(direct or relative path to file)
  • maxLine: max number of last lines to read in

• readFromText(text, maxLine): String

  • text: multiline string
  • maxLine: max number of last lines to read in

• readArrayFromText(text, maxLine): String

  • text: multiline string
  • maxLine: max number of last lines to read in

• linesToArray(text): Array

  • text: multiline string

License

MIT License

End

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http://www.easyproject.cn

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