BBEdit Codeless Language Module for TypeScript syntax coloring and class/interface/function folding.

TypeScript.plist

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<!-- https://gist.github.com/isao/5f6fbe89a438086c36d8
BBEdit Language Module for TypeScript

Put this file in
   ~/Library/Application Support/BBEdit/Language Modules
or equivalent.

Forked from
- https://gist.github.com/davethesoftwaredev/4056693
- https://gist.github.com/vtbassmatt/7242970

Which in turn were based on the language file for CoffeeScript found at
http://joyofmodeling.org/index.php/OSX/coffeescript-syntax-coloring-in-text-wrangler.html

See also http://www.barebones.com/support/develop/

-->
<plist version="1.0">
<dict>
    <key>BBEditDocumentType</key>
    <string>CodelessLanguageModule</string>

    <key>BBLMLanguageDisplayName</key>
    <string>TypeScript</string>

    <key>BBLMLanguageCode</key>
    <string>TypS</string>

    <key>BBLMColorsSyntax</key>
    <true/>

    <key>BBLMScansFunctions</key>
    <true/>

    <key>BBLMIsCaseSensitive</key>
    <true/>

    <key>BBLMKeywordList</key>
    <array>
        <string>abstract</string>
        <string>any</string>
        <string>arguments</string>
        <string>Array</string>
        <string>as</string>
        <string>async</string>
        <string>await</string>
        <string>bool</string>
        <string>boolean</string>
        <string>Boolean</string>
        <string>break</string>
        <string>case</string>
        <string>catch</string>
        <string>class</string>
        <string>const</string>
        <string>constructor</string>
        <string>continue</string>
        <string>Date</string>
        <string>debugger</string>
        <string>declare</string>
        <string>default</string>
        <string>delete</string>
        <string>do</string>
        <string>else</string>
        <string>enum</string>
        <string>Error</string>
        <string>export</string>
        <string>extends</string>
        <string>false</string>
        <string>finally</string>
        <string>for</string>
        <string>from</string>
        <string>function</string>
        <string>Function</string>
        <string>get</string>
        <string>if</string>
        <string>implements</string>
        <string>import</string>
        <string>in</string>
        <string>Infinity</string>
        <string>instanceof</string>
        <string>interface</string>
        <string>isNaN</string>
        <string>keyof</string>
        <string>let</string>
        <string>Math</string>
        <string>module</string>
        <string>namespace</string>
        <string>NaN</string>
        <string>new</string>
        <string>null</string>
        <string>number</string>
        <string>Number</string>
        <string>Object</string>
        <string>of</string>
        <string>private</string>
        <string>Promise</string>
        <string>protected</string>
        <string>public</string>
        <string>RegExp</string>
        <string>readonly</string>
        <string>return</string>
        <string>self</string>
        <string>set</string>
        <string>static</string>
        <string>string</string>
        <string>String</string>
        <string>super</string>
        <string>switch</string>
        <string>then</string>
        <string>this</string>
        <string>throw</string>
        <string>true</string>
        <string>try</string>
        <string>type</string>
        <string>typeof</string>
        <string>undefined</string>
        <string>unknown</string>
        <string>var</string>
        <string>void</string>
        <string>while</string>
        <string>with</string>
        <string>yield</string>
    </array>

    <key>BBLMSuffixMap</key>
    <array>
        <dict>
            <key>BBLMLanguageSuffix</key>
            <string>.ts</string>
        </dict>
        <dict>
            <key>BBLMLanguageSuffix</key>
            <string>.tsx</string>
        </dict>
    </array>

    <key>BBLMBalanceSpecialRunKinds</key>
    <array>
        <string>com.barebones.bblm.JavaScript.regexp</string>
        <string>com.barebones.bblm.syntax-error</string>
    </array>

    <key>Language Features</key>
    <dict>
        <key>Identifier and Keyword Character Class</key>
        <string>0-9A-Z_a-z$</string>

        <key>Comment Pattern</key>
        <string><![CDATA[(?x:
            (?>  (?<!\\)    //  .*      $   ) |
            (?> /\* (?s:.*?) (?> \*/ | \z ) )
        )]]></string>

        <key>Function Pattern</key>
        <string><![CDATA[(?x:
            (?P<leadspace>^[ \t]*)
            (?P<function>
                (?>export\s+)?
                (?>abstract\s+)?
                (?>class|interface|function)\s+
                    (?P<function_name>
                        ([A-Za-z_$][\w$.]*)
                    )
                (?s:.+?)
                \r(?P=leadspace)\}
            )
        )]]></string>

        <key>String Pattern</key>
        <string><![CDATA[(?x:
            (?> "   [^"\r]*   ") |
            (?> '   [^'\r]*   ') |
            (?> `   [^`]*     `)
        )]]></string>

        <key>Skip Pattern</key>
        <string><![CDATA[
        (?x:
            (?P>comment) |
            (?P>string)
        )]]></string>

    </dict>
</dict>
</plist>

I replaced some (?: with (?>, and tweaked the function pattern. Perf issue seems to have gone away, perhaps because of v12.1 update to 64 bit.