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    line-terminators

    2.0.0 • Public • Published

    Little tool to identify and convert line terminators from strings.

    Install

    npm i line-terminators
    

    Usage

    Identify line terminators from a string

    import lt from 'line-terminators'
    
    lt.identify('abc\ndef') // => "LF"
    
    lt.identify('abc\r\ndef') // => "CRLF"
    
    lt.identify('abcdef') // => "NONE"

    Convert a string's line terminators to another format

    import lt from 'line-terminators'
    
    lt.convert('abc\ndef', 'CRLF') // => "abc\r\ndef"
    
    lt.convert('abc\r\ndef', 'LF') // => "abc\ndef"
    
    // It will keep the original line terminators if the target is NONE
    lt.convert('abc\r\ndef\r\nghi', 'NONE') // => "abc\r\ndef\r\nghi"
    
    // If you want it to delete the line terminators when the target is NONE,
    // then pass the third parameter as `true`
    
    lt.convert('abc\r\ndef\r\nghi', 'NONE', true) // => "abcdefghi"

    Note: Passing null or undefined works the same as 'NONE'

    Copy the line terminators from a string into another

    import lt from 'line-terminators'
    
    lt.copy('abc\r\ndef\r\nghi', 'tuv\nxyz') // => "tuv\r\nxyz"
    
    lt.copy('abc\ndef\nghi', 'tuv\r\nxyz') // => "tuv\nxyz"
    
    // Keeps line terminators when the source string has no line terminators
    
    lt.copy('abcdefghi', 'tuv\nxyz') // => "tuv\nxyz"
    
    lt.copy('abcdefghi', 'tuv\r\nxyz') // => "tuv\r\nxyz"
    
    // If you want it to delete the line terminators when the source string has no
    // line terminators, then pass the third parameter as `true`
    
    lt.copy("abcdefghi", "tuv\nxyz", true) // => "tuvxyz"
    lt.copy("abcdefghi", "tuv\r\nxyz", true) // => "tuvxyz"

    Real-life use case

    Imagine you want to read a JSON file, manipulate it and save it. You would probably write something as simple as:

    const content = JSON.parse(fs.readFileSync(filePath))
    
    content.myProperty = 'my value'
    
    fs.writeFileSync(filePath, JSON.stringify(content, null, 2))

    This should be ok for most cases, but if you are working on a Windows machine and the original file was written in a POSIX machine, then you're also changing the line terminators from LF to CRLF.

    Also, imagine that myProperty already had my value in the original file. It will end up producing no changes to your content, but the file will still be different. If you use git, you will see a file change.

    You may even try to prevent writing the file if it has no changes, like:

    const contentString = fs.readFileSync(filePath)
    
    const contentObject = JSON.parse(contentString)
    
    contentObject.myProperty = 'my value'
    
    const result = JSON.stringify(contentObject, null, 2)
    
    if (result === contentString) {
      return
    }
    
    fs.writeFileSync(filePath, result)

    But result === contentString would evaluate to false, as the line terminators are different between those strings.

    By using this little tool, you could do:

    import lt from 'line-terminators'
    
    const contentString = fs.readFileSync(filePath)
    
    const contentObject = JSON.parse(contentString)
    
    contentObject.myProperty = 'my value'
    
    let result = JSON.stringify(contentObject, null, 2)
    
    // Copy the line terminators from contentString to result
    result = lt.copy(contentString, result)
    
    if (result === contentString) {
      return
    }
    
    fs.writeFileSync(filePath, result)

    result === contentString would now evaluate to true, since the result now uses the same line terminators as the contentString string.

    Install

    npm i line-terminators

    DownloadsWeekly Downloads

    73

    Version

    2.0.0

    License

    ISC

    Unpacked Size

    10.4 kB

    Total Files

    11

    Last publish

    Collaborators

    • pdcmoreira