chore: change target to es2015 (#260)

Signed-off-by: Todd Baert <[email protected]>

Author: toddbaert

README.md

@@ -38,6 +38,14 @@ const value = await client.getBooleanValue('enabled-new-feature', false);
 
 ## Development
 
+### System Requirements
+
+node 16+, npm 8+ are recommended.
+
+### Compilation target(s)
+
+We target `es2015`, and publish both ES-modules and CommonJS modules.
+
 ### Installation and Dependencies
 
 Install dependencies with `npm ci`. `npm install` will update the package-lock.json with the most recent compatible versions.

tsconfig.json

@@ -11,7 +11,7 @@
     // "disableReferencedProjectLoad": true,             /* Reduce the number of projects loaded automatically by TypeScript. */
 
     /* Language and Environment */
-    "target": "ES2020",                                  /* Set the JavaScript language version for emitted JavaScript and include compatible library declarations. */
+    "target": "ES2015",                                  /* Set the JavaScript language version for emitted JavaScript and include compatible library declarations. */
     "lib": ["ES2020"],                                        /* Specify a set of bundled library declaration files that describe the target runtime environment. */
     // "jsx": "preserve",                                /* Specify what JSX code is generated. */
     // "experimentalDecorators": true,                   /* Enable experimental support for TC39 stage 2 draft decorators. */