Blazorme.Diff 26.9.14

Blazorme.Diff

Diff component library for Blazor apps.

Requires .NET 10. Earlier versions targeted netstandard2.1 and net5.0, which are no longer supported. The library will render diff of the two input strings in different output display formats. Output is always in HTML and currently 3 output display formats are provided via OutputFormat parameter:

• Inline: Inlined format. Intented for HTML inputs although plain text can also be used.
• Row: Line by line format for text inputs.
• Column: Side by side format for text inputs.

For html diff, two show difference levels are provided via Style parameter:

• Word: Diff will be displayed based on words. This is default.
• Char: Diff will be displayed based on characters.

Use DemoApp as a reference for your implementation.

Third Party Packages

The following packages have been used:

• htmldiff.net: GitHub, NuGet
• diff: GitHub, jsdelivr (JS interop)
• diff2html: GitHub, jsdelivr (JS interop)

Installation

• Install NuGet package:

  Install-Package Blazorme.Diff

• Using:

In _Imports.razor add:

  @using Blazorme

For API calls from code behine add:

  using Blazorme;

• Inject

If you like to use API from code behind, inject IDiff:

  [Inject]
  private IDiff DiffApi { get; set; } = default!;

• JS and CSS references:

None required. Since 26.9.8 the package ships jsdiff and diff2html and loads them on demand, so there is nothing to add to index.html or _Host.cshtml.

Earlier versions required three CDN references, and omitting any of them failed at runtime with a JS interop error. If your app still has them they remain harmless: the loader skips a library whose global is already defined, so nothing is fetched twice.

The bundled components and their licences are listed in THIRD-PARTY-NOTICES.txt inside the package.

• Service addition:

Add the following entires to Program.cs in Main (WebAssembly) or Startup.cs in Configure (Server) function.

  using Blazorme;
  
  ...
  
  Main
  {
      ...
      builder.Services.AddDiff();
      ...
  }

  Configure
  {
      ...
      services.AddDiff();
      ...
  }

Parameters

    public class DiffInputTitle
    {
        public const string First = "First";
        public const string Second = "Second";
    }

   public enum DiffOutputFormat
    {
        Inline,
        Row,
        Column,
    }

    public enum DiffStyle
    {
        Word,
        Char
    }

Component Usage

In your Blazor page, add the Diff entry for the desired output format as shown below:

For Inline format

No need to specify titles or style for inline as they are are not used for this format. Also OutputFormat is Inline by default, hence no need to specify the OutputFormat explicitly.

  <Diff FirstInput="first input text"
        SecondInput="second input text"/>

For Row or Column formats

  <Diff FirstInput="first input text"
        SecondInput="second input text"
        FirstTitle="first title text displayed on the top of the rendered table"
        SecondTitle="second title text displayed on the top of the rendered table"
        OutputFormat=@DiffOutputFormat.Row
        Style=@DiffStyle.Word />
        or
        OutputFormat=@DiffOutputFormat.Column
        Style=@DiffStyle.Char />

API Usage

The Diff component can also be used as a library to get diff or html diff output strings with API calls from code behind. The API interface is defined in IDiff.cs as follows:

        public Task<string> GetAsync(string firstInput, string secondInput, 
            string firstTitle = DiffInputTitle.First, string secondTitle = DiffInputTitle.Second);

        public Task<string> GetHtmlAsync(string firstInput, string secondInput,
            string firstTitle = DiffInputTitle.First, string secondTitle = DiffInputTitle.Second,
            DiffOutputFormat outputFormat = DiffOutputFormat.Inline,
            DiffStyle style = DiffStyle.Word);

Example

Inject IDiff and call API functions.

       [Inject]
        private IDiff DiffApi { get; set; } = default!;

        ...
        
        public async Task Sample()
        {
            var firstInput = "Hello World";
            var secondInput = "Hell World!";
            var diff = await DiffApi.GetAsync(firstInput, secondInput);
            var diffHtml = await DiffApi.GetHtmlAsync(firstInput, secondInput, 
                DiffInputTitle.First, DiffInputTitle.Second, 
                DiffOutputFormat.Row, DiffStyle.Word);
        }

The above code will produce the following outputs:

diff:

===================================================================
--- First
+++ Second
@@ -1,1 +1,1 @@
-Hello World
\ No newline at end of file
+Hell World!
\ No newline at end of file

diffHtml:

<div class="d2h-wrapper">
    <div id="d2h-096910" class="d2h-file-wrapper" data-lang="">
    <div class="d2h-file-header">
    <span class="d2h-file-name-wrapper">
    <svg aria-hidden="true" class="d2h-icon" height="16" version="1.1" viewBox="0 0 12 16" width="12">
        <path d="M6 5H2v-1h4v1zM2 8h7v-1H2v1z m0 2h7v-1H2v1z m0 2h7v-1H2v1z m10-7.5v9.5c0 0.55-0.45 1-1 1H1c-0.55 0-1-0.45-1-1V2c0-0.55 0.45-1 1-1h7.5l3.5 3.5z m-1 0.5L8 2H1v12h10V5z"></path>
    </svg>    <span class="d2h-file-name">First → Second</span>
    <span class="d2h-tag d2h-moved d2h-moved-tag">RENAMED</span></span>
    </div>
    <div class="d2h-file-diff">
        <div class="d2h-code-wrapper">
            <table class="d2h-diff-table">
                <tbody class="d2h-diff-tbody">
                <tr>
    <td class="d2h-code-linenumber d2h-info"></td>
    <td class="d2h-info">
        <div class="d2h-code-line d2h-info">@@ -1,1 +1,1 @@</div>
    </td>
</tr><tr>
    <td class="d2h-code-linenumber d2h-del d2h-change">
      <div class="line-num1">1</div>
<div class="line-num2"></div>
    </td>
    <td class="d2h-del d2h-change">
        <div class="d2h-code-line d2h-del d2h-change">
            <span class="d2h-code-line-prefix">-</span>
            <span class="d2h-code-line-ctn"><del>Hello</del> World</span>
        </div>
    </td>
</tr><tr>
    <td class="d2h-code-linenumber d2h-ins d2h-change">
      <div class="line-num1"></div>
<div class="line-num2">1</div>
    </td>
    <td class="d2h-ins d2h-change">
        <div class="d2h-code-line d2h-ins d2h-change">
            <span class="d2h-code-line-prefix">+</span>
            <span class="d2h-code-line-ctn"><ins>Hell</ins> World<ins>!</ins></span>
        </div>
    </td>
</tr>
                </tbody>
            </table>
        </div>
    </div>
</div>
</div>