Build JS file for .net Constants class

Tags: PowerShell, javascript, SharePoint, SharePoint 2013

It’s pretty common practice for me to have a Constants class in all my projects, especially so in SharePoint projects where you are likely to have Field name, Content Type ID’s and probably some GUID’s that you need.

As I find myself more and more developing javascript solutions, I want access to those constants on the client side.  So taking inspiration from SharePoint (which generates a Strings object in javascript – see /_layouts/15/<lcid>/string.js, this file is auto generated by stsadm.exe.  I decided to cobble together a little script to build my js file.

Say you have a .net constants class similar to this (I also use nested classes in my constants class).

// Note: This file is autogenerated in JS for use on the client side.
//       Do NOT put any sensitive string values in it.
public static class MyStrings
{
    public static class NestedOne
    {
        public static class NestedTwo
        {
            public const string Foo = "FooString";
            public const string Bar = "BarString";

            public static class NestedThree
            {
                public const string Address1 = "AddressLine1";
            }
        }

        public static class NestedTwoTwo
        {
            public const string Location = "Location";
        }

        public const string AnotherOne = "SomeValue123";
    }
}

 

And use this PowerShell scripts (it’s a litle muddly I know, but it does work nicely!)
Note: You could remove the string builder, its just there to help with debugging.

The script is going to recursively loop through all your nested classes and build the required javascript file.

clear
$dllPath = 'C:\Constants.dll' #Path to dll containing Constants class
$constantsClassName = "MyStrings" #Name of the .net constants class
$jsClassName = "MyJsStrings"; #Name of the object in Javascript
$outputJsFilePath = "C:\dump\MyJsStrings.js" #Place to save output js file

# StringBuilder is just for debugging, you can change to simply write to stream
$sb = New-Object -TypeName "System.Text.StringBuilder"
$stream = [System.IO.StreamWriter] $outputJsFilePath

function Append([string] $val) {
	[Void]$sb.AppendLine($val)
}

Append "/* Copyright message ... "
Append " * This file has been auto generated, do NOT edit"
Append " */"

function WriteFields ([System.Reflection.MemberInfo]$member, $parent) {
	foreach($f in $member.GetFields() | where { $_.FieldType.Name -eq "String"}) {
		$t = $jsClassName+"."
		
		if(-not [System.String]::IsNullOrWhiteSpace($parent)) {
			$t += $parent+"."
		} 
		$t += $member.Name+"."+$f.Name+"='"+$f[0].GetValue($null)+"';"
		Append $t
	}
	Append ""
}

function Recurse ([System.Reflection.MemberInfo]$member, $parent) {
	WriteFields $member $parent
	
	foreach($mem in $member.GetMembers() | where { $_.IsClass -eq $true }) {
		if(-not [System.String]::IsNullOrWhiteSpace($parent)) {
			Append ($jsClassName+"."+$parent+"."+$member.Name+"."+$mem.Name+"=function(){};")
			Recurse $mem ($parent+"."+$member.Name)
		} else {		
			Append ($jsClassName+"."+$member.Name+"."+$mem.Name+"=function(){};")
			Recurse $mem $member.Name
		}
	}
}

# Load the dll
# Doing it this way doesn't lock the file, could also be done with a new AppDomain

$fileBytes = [IO.File]::ReadAllBytes($dllPath)

$assembly = [Reflection.Assembly]::Load($fileBytes)

# Get Constants class, could easily be modified if you have more that one class
$classes = $assembly.GetTypes() | where { $_.Name -eq $constantsClassName }

Append ("var "+$jsClassName+"=new Object();")

foreach($c in $classes) {
	foreach($m in $c.GetMembers() | where { $_.IsClass -eq $true }) {
		$t = $jsClassName+"."+$m.Name+"=function(){};"
		Append $t $m.Name
		Recurse $m
	}
}

Write $sb.ToString()
$stream.Write($sb.ToString())
$stream.Close();
$stream.Dispose();

 

The output is something like this…

/* Copyright message ... 
 * This file has been auto generated, do NOT edit
 */
var MyJsStrings=new Object();
MyJsStrings.NestedOne=function(){};
MyJsStrings.NestedOne.AnotherOne='SomeValue123';

MyJsStrings.NestedOne.NestedTwo=function(){};
MyJsStrings.NestedOne.NestedTwo.Foo='FooString';
MyJsStrings.NestedOne.NestedTwo.Bar='BarString';

MyJsStrings.NestedOne.NestedTwo.NestedThree=function(){};
MyJsStrings.NestedOne.NestedTwo.NestedThree.Address1='AddressLine1';

MyJsStrings.NestedOne.NestedTwoTwo=function(){};
MyJsStrings.NestedOne.NestedTwoTwo.Location='Location';

 

Add a link to that file in VS or add it to your _reference.js file and you’ll get nice intellisense!!

Hope you find this as useful as I did!




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